• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.173-178
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• 1993

In this paper, we present an algorithmic technique for determining a feedback compensator which will stabilize the interval dynamic system, specifically, the robust regulator design for interval plants. The approach taken here is to allow the system parameters to live within prescribed intervals then design a dynamic feedback compensator which guarantees closed-loop system stable. The main contribution of this paper is the idea of introducing a "simplified Kharitonov's result" for low order polynomials to search for suitable compensator parameters in the compensator parameter space to make the uncertain syste robust. We also design the robust regulator which will D-stabilize (have the closed-loop poles in the left sector only) the dynamic interval system while having good performance. The nuerical examples are given to show the substantially improved robustness which results from our approach. approach.

• Journal of Animal Environmental Science
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• v.8 no.2
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• pp.73-78
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• 2002

The experiment was carried out to investigate the optimal air velocity for improving the ventilation efficiency of duct ventilation system used in Korean swine building. The results are followed ; In 2.2 m height of duct, the air velocity of hole was 5.0 m/s as the over level of recommendation. In different hole interval, the air velocity was various of 4.6${\sim}$11.6 m/s in narrow hole interval, 5.4${\sim}$10.9 m/s in broad hole interval. But the air velocity was 6.6${\sim}$7.7 m/s in duct system pierced hole with equal interval, and it was equal velocity in different parts of duct in this hole interval.

• Journal of the Korea Society of Computer and Information
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• v.24 no.10
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• pp.57-64
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• 2019

In this paper, we study a polynomially solvable case of the inverse interval graph coloring problem. Given an interval graph associated with a specific interval system, the inverse interval graph coloring problem is defined with the assumption that there is no proper K-coloring for the given interval graph, where K is a fixed integer. The problem is to modify the system of intervals associated with the given interval graph by shifting some of the intervals in such a way that the resulting interval graph becomes K-colorable and the total modification is minimum with respect to a certain norm. In this paper, we focus on the case K = 1 where all intervals associated with the interval graph have length 1 or 2, and interval displacement is only allowed to the righthand side with respect to its original position. To solve this problem in polynomial time, we propose a two-phase algorithm which consists of the sorting and First Fit procedure.

• Journal of Bio-Environment Control
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• v.1 no.2
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• pp.169-174
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• 1992

This experiment was carried out to investigate the possibility of practical use of intermittent soaking system(ISS) in hydroponicaly growing tomato. There were four treatments which were NFT, Aeroponics, and ISS with 10 and 15 minute soaking intervals. 1. Plant height is highest in NFT, but main root length is longest in ISS. While stem diameter and leaf number were not significantly difference. 2. Fresh and dry weight were heavier in NFT than those of other systems at early growth stage, but the heavier in ISS system, the growth more develop. 3. In 43 days after treatment, the number of flowerlet was largest in aeroponics, and then ISS and NFT in order. Fruit weight per plant was also heaviest in aeroponics. 4. Average yield per plant were 1929.1g in aeroponics, 1475.2g in ISS with 10 minute soaking interval, 1276.2g in NFT and 1084.8g in ISS with 15 minute soaking interval. 5. Average fruit number per plant were 11.0 in aeroponics, 9.7 in NFT, 8.3 in ISS with 15 minute soaking interval, and 7.7 in ISS with 10 minute soaking interval. Average fruit weight were 192.9g in aeroponics, 172.4g in ISS with 10 minute soaking interval, 134.0g in NFT and 126.0g in ISS with 15 minute soaking interval. 6. Average fruit length was longer in aeroponics and ISS with 10 minute soaking interval than in the NFT and ISS with 15 minute soaking interval. Average fruit width was similarly wider in NFT, aeroponics and ISS with 10 minute soaking interval than in ISS with 15 minute soaking interval.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.5
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• pp.370-374
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• 2009

In this paper we propose an adjustment algorithm for bandwidth grant interval of UGS class flows the overload status of certain frames occurs due to the pre-defined grant interval mechanism of UGS class. In IEEE 802.16/WiBro systems, UGS class is the highest priority to guaranteed QoS Parameters. However, existing grant interval mechanisms of UGS class do not consider the condition that the grant interval of multiple UGS class flows overlaps with certain frames, and thus it causes the overload status in the system. Therefore, the system cannot be guaranteed QoS for UGS class flows. In this paper, we show the occurrence of the problem through simulation studies and propose an adjustment algorithm to solve the problem. Our simulation results show that there is performance improvement in the proposed algorithm. We expect that the real system in which the proposed scheme is applied can provide more stable QoS services by reducing the delay problem that occurs due to the occurrence of the existing grant interval problem of UGS class.

• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.504-509
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• 2022

In this paper, we deal with the stability condition of linear time-varying interval discrete systems with time-varying delays and unstructured uncertainty. For the time-varying interval discrete system which has interval matrix as its system matrices, time-varying delay time within some interval value and unstructured uncertainty which can include non-linearity and be expressed by only its magnitude, the stability condition is proposed. Compared with the previous result derived by using a upper bound solution of the Lyapunov equation, the new result is derived by the form of simple inequality based on Lyapunov stability condition and has the advantage of being more effective in checking stability. Furthermore, the proposed condition is very comprehensive, powerful and inclusive the previously published conditions of various linear discrete systems, and can be expressed by the terms of magnitudes of the time-varying delay time and uncertainty, and bounds of interval matrices. The superiority of the new condition is shown in the derivation, and the usefulness and advantage of the proposed condition are examined through numerical example.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.8
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• pp.462-470
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• 2003

This paper presents an algorithm of identifying parametric uncertainty by way of an interval model. For a given set of frequency response data from an uncertain linear SISO system of which the upper and the lower bounds of both magnitude and phase responses are represented, the proposed algorithm consists of two main parts: first, the nominal model is identified by using Least Square Estimation (LSE), and then an interval model is constructed by expanding the extremal properties of interval systems, so that tightly enclose the given envelopes within those of interval model. Two numerical examples are given to demonstrate and verify the developed algorithm. The identified interval model can be used for evaluating the worst case performance and stability margins against parametric uncertainty by using some extremal properties on interval systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.474-481
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• 2013

It is anticipated that AC distribution system can be replaced by DC distribution system in the near future because of the operation of various distributed source or microgrid system. However DC distribution system replacing 22.9kV AC distribution line is not sufficiently studied still. This paper describes lightning overvoltage analysis among many research fields should be studied to realize DC overhead distribution systems. DC distribution system is modeled using EMTP and overvoltage is analyzed according to interval of arrestor location, earth interval of overhead grounding wire and grounding resistance. It is evaluated that analysis results can be effectively used to design of future DC distribution system.

• Journal of Advanced Navigation Technology
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• v.25 no.6
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• pp.551-556
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• 2021

In this paper, we deal with the stability condition of linear interval discrete systems with time-varying delays and unstructured uncertainty. For the interval discrete system which has interval matrix as its system matrices, time-varying delay time within some interval value and unstructured uncertainty which can include non-linearity and be expressed by only its magnitude, the stability condition is proposed. Compared with the previous result derived by using a upper bound solution of the Lyapunov equation, the new results are derived by the form of simple inequality based on Lyapunov stability condition and have the advantage of being more effective in stability application. Furthermore, the proposed stable conditions are very comprehensive and powerful, including the previously published stable conditions of various linear discrete systems. The superiority of the new condition is proven in the derivation process, and the utility and superiority of the proposed condition are examined through numerical example.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1153-1156
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• 2002

In this parer, a high quality mesh generation method by using interval arithmetic is proposed. In the proposed method, the variance of a tangent vector at the point is considered by the automatic differentiation. From the variance, sampling points on the surface are judged whether it is adequate or not, which is calculated by the interval arithmetic. Then Delaunay triangulation is performed to the obtained sampling points, and a set of meshes is generated. The proposed method is hard to overlook the local variation of surfaces.