• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.5
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• pp.65-73
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• 2004

CMG(Control Momentum Gyro) is a control device being used for spacecraft attitude control constructing relatively large amount of torque compared to conventional body-fixed reaction wheels. The CMG produces gyroscopic control torque by continuously varying the angular momentum vector direction with respect to the spacecraft body. The VSCMG(Variable Speed Control Momentum Gyro) has favorable advantages with variable speed to lead to better control authority as well as singularity avoidance capability. Attitude dynamics with a VSCMG mounted on a two-axis gimbal system are derived in this study. The dynamic equation may be considered as an extension of the single-axis counterpart. Also, a feedback control law design is addressed in conjunction with the dynamic equations of motion.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.7
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• pp.75-84
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• 2003

To reduce the effects of the uncertainties due to the modeling error and aerodynamic coefficients, a nonlinear adaptive control system based on neural networks is proposed . Neural networks parameters are adjusted by using an adaptive law. The sliding mode control scheme is used to compensate for the effect of the approximation error of neural networks. Control parameters and neural networks structures are optimized to obtain better performance by using the genetic algorithm. By introducing the concept of multi-groups of populations, the genetic algorithm is modified so that individuals and groups can be simultaneously evolved . To verify the performance of the pro posed algorithm, the optimized neural networks control system is applied to an aircraft longitudinal dynamics.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.2
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• pp.162-169
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• 2011

The flight control system utilize RSS(Relaxed Static Stability) criteria in both longitudinal axes to achieve performance enhancements and improve stability. The aircraft using digital flight-by-wire flight control system receives aircraft flight conditions such as pitch, roll and yaw rate, normal acceleration from RSA(Rate Sensor Assembly) and ASA(Acceleration Sensor Assembly). These sensors has permissible measurement error related to system safety of an aircraft but, unexpected flight motions are happened by sensing errors such as offset, noise and etc. The unexpected pitch down tendency occurred by ASA sensor bias in 1g level flight with pilot hands-off. This paper addresses the design and verification of flight control law to improve of pitch down or up tendency caused by ASA sensor bias. The result of analysis and flight test reveals that pitch down tendency can be improved by pitch attitude feedback system.

• Journal of Korea Technology Innovation Society
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• v.20 no.4
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• pp.989-1014
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• 2017

Major advanced countries pursuing accountability for research and development are carrying out gendered innovations by recognizing the importance of sex and gender analysis in science research and technology development. Korea needs to actively promote gendered innovations as a strategy moving from Fast Follower to First Mover. In order to promote gendered innovations in the science, technology and ICT fields, policies of integrating the gender dimension in the process of research from research design to the analysis of research outcomes should be declared and research support measures should be introduced from the proposal evaluation for the gendered innovations. In particular, in order to support the new gendered innovations research systematically in Korea's R & D system, a legal basis must precede. In this study, we propose an amendment to the law related to gender innovation by analyzing the cases in foreign countries.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.6
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• pp.40-50
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• 2002

In this paper, we present a GA(Genetic Algorithm) approach to select weighting matrices of an optimal LQ(Linear Quadratic) controller for SVC(Static VAR Compensator). A SVC, one of the FACTS(Flexible AC Transmission System), constructed by a FC(Fixed Capacitor) and a TCR(Thyristor Controlled Reactor), was designed and implemented to improve the damping of a synchronous generator, as well as to control the system voltage Also, a design of LQ controller depends on choosing weighting matrices. The selection of weighting matrices which is not a trivial solution is usually carried out by trial and error. We proposed an efficient method using GA of finding weighting matrices for optimal control law. Thus, we proved the usefulness of proposed method to improve the stability of single machine-infinite bus with SVC system by eigenvalues analysis and simulation.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.3
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• pp.1-16
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• 2003

The ultimate goal of this research is to establish the movement rights of people with physical disabilities. To achieve this goal, the authors have investigated the regulation and restrictions of physical facilities to guarantee the movement rights and investigated how well these facilities were constructed. The authors then have analyzed and compared the results. The purposes of this research are as follows. First, the authors investigated and analyzed the present conditions of selected public facilities to propose improvement measures for the disabled, pregnant and seniors so that they could actively participate in cultural activities as normal people do. Second, the designs resulting from this research are provided so as to be helpful to disabled people in everyday life, which is different from previously conducted research. Third, the authors have selected facilities with outdoor areas to differentiate the results from those reported recently through research conducted on indoor buildings. The final step of this research is to provide basic design data on outdoor areas to establish true movement rights for the disabled. According to these research findings, the shortest moving distance cannot be guaranteed only by establishing facilities that follow the Article 3 law about guarantee of convenience improvement for the disabled. If the movement path is not regulated, the facility standards may not exist in one part and the part itself may become obscured and the distance could become longer than necessary. Accordingly, for real movement rights the movement path should be guaranteed not to be violated by other obstacles. The results of this study offer convenience when moving within the outdoor space of cultural facilities by providing direct information for the disabled. The value of this study is that it is the first study on movement rights and movement paths for people with physical disabilities.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.169-170
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• 2012

The efforts for improving 'Maritime Traffic Safety Assessment Scheme(MTSA scheme)' have continued to the present since May 27th, 2009. But recently, there's a controversy about whether it has been performed properly or the results is significant. These new discussions were arose from lack of validity and appropriateness we had yet to find. At this point, it needs to establish sound MTSA scheme through the comprehensive review. This research developed a suitable meta-evaluation model for MSTA with applying theory of the teta-evaluation, that is the evaluation of evaluations and verified by using meta-evaluation methods like as literature studies, expert reviews, surveys and etc. The results of this study can be used to evaluate MTSA activities and it will contribute to improving MTSA scheme.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2189-2194
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• 2009

The automatic hot gas by-pass technique is applied to control the capacity of refrigeration and air-conditioning system when operating at part load. In the scheme, the hot gas from the compressor is extracted and injected into the outlet of an evaporator through a hot gas by-pass valve. Thus, In this paper, the hot gas by-pass scheme for CO2 is discussed and analyzed on the basis of mass and energy conservation law. A comparative study of the schemes is performed in terms of the coefficiency of performance (COP) and cooling capacity. The operating parameters considered in this study include compressor efficiency, superheating degree, outlet temperature of gas cooler and evaporating temperature in the R744 vapor compression cycle. The main results were summarized as follows : the superheating degree, outlet temperature and evaporating temperature of R744 vapor compression refrigeration system have an effect on the cooling capacity and COP of this system. With a thorough grasp of these effect, it is necessary to design the compression refrigeration cycle using R744.

• The Korean Nurse
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• v.31 no.3
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• pp.62-75
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• 1992

This study was done to suggest basic modifications in the present situation for the family of women in labour which is a separation management method. The study design was a descriptive study. The number of the subjects were 80. they were husbands, mothers in law, and mothers of women in labour who were full term and for whom there were no complications, either for the mother or the fetus. Data collection was done with a structured questionnaire which was analyzed using frequencies. The results were as follows, 1. Most of the subjects(95.0%) wanted to participate in the labour process. 2. The subjects wanted to support the women in labour by way of encouraging(95.0%), consoling (95.0%), listening to(75.0%), praying with(68.8%), hand holding(97.5%), stroking(63.8%), helping with respiration control(50.0%), maintaining relaxation(46.3%), changing position(58.8%), and illustration (58.8 %). 3. The subjects answered that they expected their participation to have the effect of an easier labour course(52.5%), security for the women in labour(95.0%), and providing a better relationship between the women in labour(66.3%) and the new baby(55.0%). 4. The priority of the response as to who is the best supporter was husband, and mother of the women in labour in that order. It can be concluded that nurses maintained a management method which ignored the needs of the families of women in labour. If given consideration is to be given to these subjects, future programs should initiate ways to let the families participate in the labour process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.1056-1062
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• 2004

Migration of low molecular weight components from expanded polystyrene (ESP) to distilled water was measured at different temperature conditions. Overall migration and specific monomer migration were measured. Diffusion model based on Fick's law was used to determine the apparent diffusion coefficients at various experimental conditions. The overall and specific migration levels were estimated to give some practical implications for regulatory guideline development and safe package design. Diffusion coefficients for overall migration in KMnO$_4$ oxidizable extractives and specific migration of styrene monomer from ESP at 6$0^{\circ}C$ were 0.030 and 6.8${\times}$10$^{-5}$ $\textrm{mm}^2$/h, respectively. Their temperature dependence could be explained by Arrhenius equation with respective activation energies of 80.5 and 98.6 kJ/㏖. Experimental conditions ensuring desired migration level were suggested for reliable examination of migration from the packaging material. Some explanatory estimations of migrations were given for some typical conditions of potential usages.