• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1290-1298
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• 2000

Multimedia Systems such as VOD(Video On Demand) and MOD (Multimedia On Demand) need to support continuous media operations which are randomly called by concurrent users and require that stored media be accessed in real-tim. To satisfy such a requirements, disk arrays consisting of multiple disks are generally used as storage systems. Under the real-time environments to provide users with accessing continuous media in the parallel and concurrent manner, storage systems should be able to deal with user requests independently. In this paper, we present a new fault-tolerant continuous media storage system called PADA(PRR\ulcorner bAsed Disk Array), which is based on a PRR\ulcorner (Prime Round Robin with Grouped Parties) disk placement scheme with enhanced reliability nd load-balancing. We have compared and evaluated the storage space overhead for fault-tolerance, the reliability of diks array systems, the degree of disk load0-balancing, the demanded buffer space, the maximum number of users being capable of supporting and the fault recovery overhead for PADA, RAID 5 and Declustered storage systems. According to the results, PADA is the best among them in that PADA satisfies load-balancing more effectively and servces more user in case of arbitrary-rate retrievals.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1759-1771
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• 2017

In this paper, an improved continuous integral variable structure systems(ICIVSS) with the prescribed control performance is designed for simple regulation controls of uncertain general linear systems. An integral sliding surface with an integral state having a special initial condition is adopted for removing the reaching phase and predetermining the ideal sliding trajectory from a given initial state to the origin in the state space. The ideal sliding dynamics of the integral sliding surface is analytically obtained and the solution of the ideal sliding dynamics can predetermine the ideal sliding trajectory(integral sliding surface) from the given initial state to the origin. Provided that the value of the integral sliding surface is bounded by certain value by means of the continuous input, the norm of the state error to the ideal sliding trajectory is analyzed and obtained in Theorem 1. A corresponding discontinuous control input with the exponential stability is proposed to generate the perfect sliding mode on the every point of the pre-selected sliding surface. For practical applications, the discontinuity of the VSS control input is approximated to be continuous based on the proposed modified fixed boundary layer method. The bounded stability by the continuous input is investigated in Theorem 3. With combining the results of Theorem 1 and Theorem 3, as the prescribed control performance, the pre specification on the error to the ideal sliding trajectory is possible by means of the boundary layer continuous input with the integral sliding surface. The suggested algorithm with the continuous input can provide the effective method to increase the control accuracy within the boundary layer by means of the increase of the $G_1$ gain. Through an illustrative design example and simulation study, the usefulness of the main results is verified.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1930-1933
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• 1991

In this paper, the robustness of self turning controller on the continuous time-delay system is investigated. The polynomial identification method using continuous time exponentially weighted least square algorithm is used for estimating the time.-delay system parameters. The pole-zero and pole placement method are adopted for the control algorithm. On considering the control weighting factor and reliability filter the effect of unmodeled dynamics of the plant are examined by the simulation.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.6
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• pp.565-570
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• 2002

We introduce the concepts of fuzzy H-continuity and fuzzy strongly closed graph, respectively and investigate some of their properties.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.1
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• pp.33-37
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• 2011

We introduce the concepts of interval-valued fuzzy m${\beta}$-open sets and interval-valued fuzzy m${\beta}$-continuous mappings. And we study some characterizations and properties of such concepts.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.361-364
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• 2001

The aim of this paper is to continue the study of fuzzy quasi-continuous mappings due to Park et at. (12) on fuzzy bitopological spaces.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.2
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• pp.244-249
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• 2011

We introduce the concepts of fuzzy pairwise ${\beta}$-(r, s)-continuous mappings and fuzzy pairwise ${\beta}$-(r, s)-open mappings in smooth bitopological spaces and then we investigate some of their characteristic properties.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.12 no.4
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• pp.319-323
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• 2012

We define and characterize a somewhat fuzzy irresolute continuous mapping and a somewhat fuzzy irresolute semiopen mapping on a fuzzy topological space. Besides, some interesting properties of those mappings are given.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.129-130
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• 2008

In this paper, we introduce the concept of generalized fuzzy (r,s)-closed sets on intuitionistic fuzzy topological spaces in ${\v{S}ostak's$ sense. Using this concept, we introduce the notions of generalized fuzzy (r,s)-continuous mappings, and then we investigate some of their properties.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.29-32
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• 2001

This paper presents matrix inequality conditions for H$_2$optimal control of linear time-invariant descriptor systems in continuous and discrete time cases, respectively. First, the necessary and sufficient condition for H$_2$control and H$_2$controller design method are expressed in terms of LMls(linear matrix inequalities) with no equality constraints in continuous time case. Next, the sufficient condition for H$_2$control and H$_2$controller design method are proposed by matrix inequality approach in discrete time case. A numerical example is given in each case.