• 충청수학회지
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• 제34권3호
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• pp.189-207
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• 2021

In this paper, we consider the approximate controllability for a class of semilinear integro-differential functional control equations in which nonlinear terms of given equations satisfy quasi-homogeneous properties. The main method used is to make use of the surjective theorems that is similar to Fredholm alternative in the nonlinear case under restrictive assumptions. The sufficient conditions for the approximate controllability is obtain which is different from previous results on the system operator, controller and nonlinear terms. Finally, a simple example to which our main result can be applied is given.

• Journal of Applied and Pure Mathematics
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• 제5권1_2호
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• pp.23-40
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• 2023

This paper is concerned by the controllability results of impulsive neutral stochastic functional integrodifferential equations (INSFIDEs) driven by fractional Brownian motion with infinite delay in a real separable Hilbert space. The controllability results are obtained using stochastic analysis, Krasnoselkii fixed point method and the theory of resolvent operator in the sense of Grimmer. A practical example is provided to illustrate the viability of the abstract result of this work.

• 전기전자학회논문지
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• 제25권4호
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• pp.774-777
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• 2021

본 논문은 Charge Trap Flash using Ferroelectric(CTF-F) 구조를 가진 3D NAND Flash Memory gate controllability에 대해 분석했다. Ferroelectric 물질인 HfO₂는 polarization 이외에도 high-k 라는 특징을 가진다. 이러한 특징으로 인해 CTF-F 구조에서 gate controllability가 증가하고 Bit Line(BL)에서 on/off 전류특성이 향상된다. Simulation 결과 CTF-F 구조에서 String Select Line(SSL)과 Ground Select Line(GSL)의 채널길이는 100 nm로 기존 CTF 구조에 비해 33% 감소했지만 거의 동일한 off current 특성을 확인했다. 또한 program operation에서 channel에 inversion layer가 더 강하게 형성되어 BL을 통한 전류가 약 2배 증가한 것을 확인했다.

• Asia pacific journal of information systems
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• 제18권2호
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• pp.1-14
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• 2008

According to technology acceptance model(TAN) which is one of the most important research models for explaining IT users' behavior, on intention of using IT is determined by usefulness and ease of use of it. However, TAM wouldn't explain the performance of using IT while it has been considered as a very good model for prediction of the intention. Many people would not be confirmed in the performance of using IT until they can control it at their will, although they think it useful and easy to use. In other words, in addition to usefulness and ease of use as in TAM, controllability is also should be a factor to determine acceptance of IT. Especially, there is a very close relationship between controllability and ease of use, both of which explain the other sides of control over the performance of using IT, so called perceived behavioral control(PBC) in social psychology. The objective of this study is to identify the relationship between ease of use and controllability, and analyse the effects of both two beliefs over performance and intention in using IT. For this purpose, we review the issues related with PBC in information systems studies as well as social psychology, Based on a review of PBC, we suggest a research model which includes the relationship between control and performance in using IT, and prove its validity empirically. Since it was introduced as qa variable for explaining volitional control for actions in theory of planned behavior(TPB), there have been confusion about concept of PBC in spite of its important role in predicting so many kinds of actions. Some studies define PBC as self-efficacy that means actor's perception of difficulty or ease of actions, while others as controllability. However, this confusion dose not imply conceptual contradiction but a double-faced feature of PBC since the performance of actions is related with both self-efficacy and controllability. In other words, these two concepts are discriminated and correlated with each other. Therefore, PBC should be considered as a composite concept consisting of self-efficacy and controllability, Use of IT has been also one of important areas for predictions by PBC. Most of them have been studied by analysis of comparison in prediction power between TAM and TPB or modification of TAM by inclusion of PBC as another belief as like usefulness and ease of use. Interestingly, unlike the other applications in social psychology, it is hard to find such confusion in the concept of PBC in the studies for use of IT. In most of studies, controllability is adapted as PBC since the concept of self-efficacy is included in ease of use explicitly. Based on these discussions, we can suggest perceived use control(PUC) which is defined as perception of control over the performance of using IT and composed of controllability and ease of use as sub-concepts. We suggest a research model explaining acceptance of IT which includes the relationships of PUC with attitude and performance of using IT. For empirical test of our research model, two user groups are selected for surveying questionnaires. In the first group, there are freshmen who take a basic course for Microsoft Excel, and the second group consists of senior students who take a course for analysis of management information by Excel. Most of measurements are adapted ones that have been validated in the other studies, while performance is real score of mid-term in each class. In result, four hypotheses related with PUC are supported statistically with very low significance level. Main contribution of this study is suggestion of PUC through theoretical review of PBC. Specifically, a hierarchical model of PUC are derived from very rigorous studies in the relationship between self-efficacy and controllability with a view of PBC in social psychology. The relationship between PUC and performance is another main contribution.

• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.623-631
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• 2005

The approximate controllability for the nonlinear control system with nonlinear monotone hemicontinuous and coercive operator is studied. The existence, uniqueness and a variation of solutions of the system are also given.

• 대한수학회보
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• 제30권2호
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• pp.277-284
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• 1993

The purpose of this paper is to prove the approximate controllability results for the delay Volterra system in the case of trajectories. In method, our paper differs from [5].

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제7권2호
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• pp.101-113
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• 2000

In this paper, we study controllability of nonlinear delay parabolic equa-tions with nonlocal initial condition under boundary input.

• 대한수학회보
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• 제36권3호
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• pp.533-541
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• 1999

In this paper, we will study controllability of some case s an initial condition $\phi$ included in some approximated phase space. To this prove we used to the Schauder fixed point theorem.

• 대한수학회보
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• 제48권4호
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• pp.705-712
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• 2011

In this paper, we investigate the boundary control of semilinear neutral evolution systems with a nonlocal condition by using the Banach fixed point theorem.

• 한국지능시스템학회논문지
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• 제13권1호
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• pp.102-106
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• 2003

In this paper, we study the controllability of fuzzy differential systems with nonlocal initial conditions. Result of this paper has improved and expanded in [5].