• 충청수학회지
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• 제34권4호
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• pp.355-368
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• 2021

In this paper, we investigate necessary and sufficient conditions for the approximate controllability for semilinear stochastic functional differential equations with delays in Hilbert spaces without the strict range condition on the controller even though the equations contain unbounded principal operators, delay terms and local Lipschitz continuity of the nonlinear term.

• Nonlinear Functional Analysis and Applications
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• 제28권2호
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• pp.407-420
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• 2023

In this manuscript, we study the sufficient conditions for controllability of Volterra-Fredholm type fractional integro-differential systems in a Banach space. Fractional calculus and the fixed point theorem are used to derive the findings. Some examples are provided to illustrate the obtained results.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제14권2호
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• pp.145-153
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• 2014

With reasonable control selections on the space of functions, various application models can take the shape of a well-defined control system on mathematics. In the credibility space, controlability management of fuzzy differential equation is as much important issue as stability. This paper addresses exact controllability for fuzzy differential equations in the credibility space in the perspective of Liu process. This is an extension of the controllability results of Park et al. (Controllability for the semilinear fuzzy integro-differential equations with nonlocal conditions) to fuzzy differential equations driven by Liu process.

• 제어로봇시스템학회논문지
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• 제10권12호
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• pp.1119-1126
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• 2004

This paper presents optimized structured treatment interruption to reduce medication and establish long-term immune response against HIV-infection. Understanding HIV-related immune system control enables better HIV therapy without using full­treatments. Discrete regimen and continuous regimen characteristics are compared. Controllability of HIV-related immune system is analyzed for better understanding of optimal control in HIV therapy. Using optimal control provides more effective therapy than the full treatment without interruption in terms of controllability analysis. Case studies indicates that the proposed therapy induces long-erm non-progression while preserving high CD4 T-helper cell count and low virus load in HIV-infected patients.

• 한국항해학회지
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• 제18권1호
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• pp.1-21
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• 1994

The safety of the ship manoeuver is dependent not only on the inherent characteristics of the ship itself and environmental conditions, but also on the skill and experience of the ship operator. As the ship operator's judgement is related to his experience and skill, based on outside information, piloted controllability also depends upon the effectiveness, accuracy and reliability of various information which is obtainable from navigational equipments and aids to navigation that are available to the ship ope-rator. Although these factors, human factors and informational factors, have been pointed out as major factors which affect the controllability of a ship, there was no a comprehensive examination on the effect of these two factors. In this thesis, therefore, an attempt was made to examine whether or not there is clear indication that these two factors affect the controllability of a ship in reality. Experiments were conducted using the port design simulator of the Korea Maritime University.

• Smart Structures and Systems
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• 제17권5호
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• pp.773-793
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• 2016

This work presents a methodology to distribute piezoelectric material for structural vibration active control. The objective is to design controlled structures with actuators which maximizes the system controllability. A topology optimization was formulated in order to distribute two material phases in the domain: a passive linear elastic material and an active linear piezoelectric material. The objective is the maximization of the smallest eigenvalue of the system controllability Gramian. Analytical sensitivities for the finite element model are derived for the objective functions and constraints. Results and comparisons with previous works are presented for the vibration control of a two-dimensional short beam.

• 대한수학회보
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• 제48권4호
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• pp.813-838
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• 2011

In this paper, we prove sufficient conditions for controllability of second order semi-linear neutral impulsive differential inclusions on unbounded domain with infinite delay in Banach spaces using the theory of strongly continuous Cosine families. We shall rely on a fixed point theorem due to Ma for multi-valued maps. The controllability results in infinite dimensional space has been proved without compactness on the family of Cosine operators.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.53-56
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• 1999

The control performance of a chemical process is determined by process structure as well as the performance of controllers. Therefore, the concept of“controllability”should be introduced in the early design stage. Structural information makes controllability assessment possible by giving insights on the pathways of disturbances in the process. In this study, a simple procedure to evaluate controllability is suggested to screen out design alternatives using relative order analysis and structural decomposition. The effectiveness of the proposed method was validated by comparing the results with the case of dynamical simulation.

• 대한간호학회지
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• 제31권2호
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• pp.232-243
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• 2001

When people undergo stressful situations such as a cancer diagnosis, they ask, "why me\ulcorner" The causal attributions people make about cancer influence what kind of coping strategies are chosen. Weiner (1979) suggested three dimensions of causal attributions: focus of causality, stability, and controllability. The purpose of the present study was to test the relation between causal attributions and self-efficacy in patients with cancer. The subjects were 194 patients who had been diagnosed cancer one year ago and attended an outpatient clinic. 1. Each mean score of causal attribution dimensions (focus of control, stability, controllability) that each patient made about cancer was 2.47, 2.73, 2.86, 3.35, and 3.28. The mean score of self-efficacy was 71.03. 2. There was a significant negative correlation between self efficacy and controllability. Particularly, there was a significant negative relationship between self efficacy and external controllability. Based upon these results, it is recommended that the developing nursing interventions to change causal attribution and self-efficacy is necessary. A number of theoretical relationships and empirical finding are confirmed by this data, and future proposals in research is suggested.

• Kyungpook Mathematical Journal
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• 제61권3호
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• pp.559-581
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• 2021

In this paper, we establish the existence of solutions and the approximate controllability for the semilinear neutral differential control system under natural assumptions such as the local Lipschitz continuity of nonlinear term. First, we deal with the regularity of solutions of the neutral control system using fractional powers of operators. We also consider the approximate controllability for the semilinear neutral control equation, with a control part in place of a forcing term, using conditions for the range of the controller without the inequality condition as in previous results.