• Advances in aircraft and spacecraft science
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• v.10 no.4
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• pp.369-391
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• 2023

In our research we have offered a solid solution for aeronautical analysis. which can guarantee the asymptotic stability of coupled nonlinear facilities. According to the theoretical solutions and methods presented, the engine of this aircraft is a small high-bypass turbofan engine. using the non-linear aero-motor control approach and this paper focuses on the power management function of the aero-motor control system. These include static controls and transient controls. A mathematical model of the high-bypass-ratio two-spool unmixed-flow aeroengine was developed through a set of nonlinear dynamic equations verified by experimental data. A single actuator using the displacement method is designed to maintain a certain level of thrust under steady-state conditions. and maintains repeatable performance during transient operation from the requested thrust phase to the next. A single controller can compensate for the effects of noise and harmonic noise at many performance points. And the dynamic performance of a single controller is satisfactory during the transient. for fairness Numerical and computer experiments are described in the perfection of the methods we offer in research.

• Journal of Mechanical Science and Technology
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• v.16 no.10
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• pp.1187-1200
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• 2002

This paper is concerned with the design or an LMI (Linear Matrix Inequality) -based H$\infty$ controller for a line of sight (LOS) stabilization system and with its robustness performance. The linearization of the system is necessary to analyze various nonlinear characteristics, but the linearization entails modeling uncertainties which reduce its performance. In addition, the stability of the LOS can be adversely affected by angular velocity disturbances while the vehicle is moving. As the vehicle accelerates, all the factors that are Ignored and simplified for the linearization tend to Inhibit the performance of the system. The robustness in the face of these uncertainties needs to be assured. This paper employs H$\infty$ control theory to address these problems and the LMI method to provide a suitable controller with minimal constraints for the system. Even though the system matrix does not have a full rank, the proposed method makes it possible to design a H$\infty$ controller and to deal with R and S matrices for reducing the system order. It can be also shown that the proposed robust controller has a better disturbance attenuation and tracking performance. The LMI method is also used to enhance the applicability of the proposed reduced-order H$\infty$ controller for the system given. The LMI-based H$\infty$ controller has superior disturbance attenuation and reference input tracking performance, compared with that of the conventional controller under real disturbances.

• Journal of Advanced Navigation Technology
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• v.20 no.5
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• pp.475-481
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• 2016

In this paper, the new stability condition of linear discrete interval time-varying systems with time-varying delay time is proposed. The considered system has interval time-varying system matrices for both non-delayed and delayed states with time-varying delay time within given interval values. The proposed condition is derived by using Lyapunov stability theory and expressed by very simple inequality. The restricted stability issue on the interval time-invariant system is expanded to interval time-varying system and a powerful stability condition which is more comprehensive than the previous is proposed. As a results, it is possible to avoid the introduction of complex linear matrix inequality (LMI) or upper solution bound of Lyapunov equation in the derivation of sufficient condition. Also, it is shown that the proposed result can include the many existing stability conditions in the previous literatures. A numerical example in the pe revious works is modified to more general interval system and shows the expandability and effectiveness of the new stability condition.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1060-1065
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• 2005

An Independent Administrative Corporation Japan Agency for Marine-Earth Science and Technology (JAMSTEC) is developing light-and-small Autonomous Underwater Vehicles (AUV)$^{1)}$, named 'MR-X1' (Marine Robot Experimental 1), which can cruise, investigate and observe by itself without human's help. In this paper, we consider the motion control problem of 'MR-X1' and derive a controller. Since the dynamic property of 'MR-X1' is changed by the influence of the speed, the mathematical model of 'MR-X1' becomes the nonlinear model. In order to design a controller for 'MR-X1', we generally apply nonlinear control theories or linear control theories with some constant speed situation. If we design a controller by applying Linear Quadratic (LQ) optimal control theory, the obtained controller only compensates t e optimality at the designed speed situation, and does not compensate the stability at another speed situations. This paper proposes a controller design method using Linear Matrix Inequalities (LMIs)$^{2),3),4)}$, which can adapt the speed variation of 'MR-X1'. And examples of numerical analysis using our designed controller are shown.

• Korean journal of communication and information
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• v.70
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• pp.66-94
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• 2015

Postcolonialism, as a school of thought, has become enormously influential for understanding the recent phenomena of globalization. While rejecting the universalizing categories of the Enlightenment, postcolonialism has called into question the old idea of culture and identity as a transcendent regime of authenticity and purity. It has also celebrated the diasporic experiences that entail porous and hybrid cultural identities as a potential site of struggle and resistance against the dominant cultural and discursive order. It is argued, however, that postcolonial theory's emancipatory claims relating to the diversified global culture tend to be complicit with transnational capitalism that brings about global issues of material as well as cultural injustice. This article, through a thorough review of the ways the postcolonial theoretical framework has been developed and appropriated by main figures in postcolonial scholarship, seeks for a theoretical and critical strategy to grasp the complex conditions of global inequality.

• International Area Studies Review
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• v.12 no.3
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• pp.25-47
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• 2008

This paper tries to explore the impact of economic globalization on social capital accumulation. To investigate direct effect, we build a model and derive a proposition which can explain the relative decline in social capital brought about by market expansion. Besides direct effect, we also explore channel effect through democracy, government size, education attainment, and inequality. We estimate direct and channel effect of globalization using cross section of 65 countries data time period 1980-1999 using three-stage least squares(3SLS). Results are in line with predictions and clearly support that globalization significantly and negatively affects social capital accumulation. Channel effect also shows that globalization has a negative effect through aggravating income inequality while it has a positive effect through higher education attainment, higher level of democracy and larger government spending. Such a net negative channel effect reinforces our prediction. As a robustness check we estimate other sets of data and the result strongly supports our theory.

• Korean Journal of Family Social Work
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• no.57
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• pp.183-215
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• 2017

This study analyzes Korean childcare policy from a caring democracy perspective by using the normative policy analysis method. In the midst of emergent new social risks engendered by low fertility and aging population, feminist scholars proposed a transformative paradigm shift from economic growth to caring oriented development on a macro scale but researches on how this grand principle can be reflected into each policy have hardly been discussed. Thus, this study intends to contribute to such policy-driven discussion by analysing childcare policy on the basis of three normative values of freedom, equality and justice re-interpreted by caring democracy theory. Following are key findings. First, childcare policy does not guarantee public value and social solidarity due to the limitations of free choice from the perspective of freedom. Secondly, gender and class stratification has been worsened in a multiple and more complicated way by adding generational and racial dimensions to the existing gender inequality and vicious circulation of private care is observed from equality perspective. Thirdly, structural inequality aggravated injustice previously accumulated in the past rather than providing flat ground by adjustment.

• Journal of Digital Convergence
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• v.18 no.3
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• pp.133-138
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• 2020

The ability to use ICT is now a prerequisite for living in the information age, and digital literacy, which can access and utilize various digital information such as online banking, shopping, news, and health care, is more important. It is increasing. Accordingly, the social inequality, or digital divide, related to accessing and accepting digital information and knowledge is also an important social issue. In particular, the digital divide by age is becoming a major issue, not only in terms of resolving social imbalances but also in resolving the structural problems of the economy in addition to the survival of the elderly. This study aims to find ways to resolve the digital gap of the elderly in terms of socioemotional selectivity theory and suggests the reasons for the elderly's less access to digital information acquisition and the implications for the solution.

• Korean Journal of Social Welfare
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• v.65 no.4
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• pp.295-315
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• 2013

The purpose of this study is to analyse the ethical basis of two influential global citizenship idea - Rawls' liberal approach and cosmopolitan republicanism - as a theory on global justice. In the aspect of deontology, Rawls' view has the limit not to reflect reciprocal obligation and duty on civil right in the era of economic globalization that inequality has been structured. But cosmopolitan republicanism has the basis of deontological justification because advocates the realization of anti-domination principle at global level. In the aspect of utilitarianism, Rawls attempts to justify the logic rejecting redistribution intra nations. But cosmopolitan republicanism has the potential to decrease maleficence at global level and to increase utility level through overcoming the structured sacrifice of the citizens of developing countries.

• The Journal of Art Theory & Practice
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• no.15
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• pp.111-135
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• 2013

This study explores gender images represented in the works of women artists from the Middle East, where male chauvinism is recognized to be more predominant than elsewhere. The artists included in this study such as Mona Hatoum, Shirin Neshat, Lida Abdul and Sigalit Landau are Post-Feminist generation of artists who were born in the Middle East but spent significant amount of time in the West. In addition, they were trained as artists under the influences of the Western Feminist Art. This particular group of female artists pays much attention to the ontological question of their identities rather than male/female inequality, and each artist represents men and women in the ways that can hardly be found in the works by women artists in the West. These artists not only connect gender identities to the socio-political geography of the Middle East but also deconstruct Western stereotypes of men and women from Arab world. The paper focuses on the way these women artists incorporate male/female vs. culture/nature dichotomies into their works to subvert the premises on which Western Feminism has been based and not only to cast light on women's freedom and their ontological conflicts but also to emphasize social suppression inflicted upon men. In such process, these artists resist stereotypical images of Middle Eastern men and women widely circulated in the mainstream media of the West.