• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.502-505
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• 2004

An intelligent digital redesign technique (IDR) for the observer-based output feedback Takagi-Sugeno (T-S) fuzzy control system with unmeasurable premise variables is developed. The considered IDR condition is cubically parameterized as convex minimization problems of the norm distances between linear operators to be matched.

• Bulletin of the Korean Chemical Society
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• v.24 no.5
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• pp.677-680
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• 2003

• Nutrition Research and Practice
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• v.9 no.6
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• pp.613-618
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• 2015

BACKGROUND/OBJECTIVES: Iron deficiency in early life is associated with developmental problems, which may persist until later in life. The question of whether iron repletion after developmental iron deficiency could restore iron homeostasis is not well characterized. In the present study, we investigated the changes of iron transporters after iron depletion during the gestational-neonatal period and iron repletion during the post-weaning period. MATERIALS/METHODS: Pregnant rats were provided iron-deficient (< 6 ppm Fe) or control (36 ppm Fe) diets from gestational day 2. At weaning, pups from iron-deficient dams were fed either iron-deficient (ID group) or control (IDR group) diets for 4 week. Pups from control dams were continued to be fed with the control diet throughout the study period (CON). RESULTS: Compared to the CON, ID rats had significantly lower hemoglobin and hematocrits in the blood and significantly lower tissue iron in the liver and spleen. Hepatic hepcidin and BMP6 mRNA levels were also strongly down-regulated in the ID group. Developmental iron deficiency significantly increased iron transporters divalent metal transporter 1 (DMT1) and ferroportin (FPN) in the duodenum, but decreased DMT1 in the liver. Dietary iron repletion restored the levels of hemoglobin and hematocrit to a normal range, but the tissue iron levels and hepatic hepcidin mRNA levels were significantly lower than those in the CON group. Both FPN and DMT1 protein levels in the liver and in the duodenum were not different between the IDR and the CON. By contrast, DMT1 in the spleen was significantly lower in the IDR, compared to the CON. The splenic FPN was also decreased in the IDR more than in the CON, although the difference did not reach statistical significance. CONCLUSIONS: Our findings demonstrate that iron transporter proteins in the duodenum, liver and spleen are differentially regulated during developmental iron deficiency. Also, post-weaning iron repletion efficiently restores iron transporters in the duodenum and the liver but not in the spleen, which suggests that early-life iron deficiency may cause long term abnormalities in iron recycling from the spleen.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.6
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• pp.700-705
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• 2012

This paper addresses an intelligent digital redesign (IDR) technique for observer-based output-feedback control systems, in order to efficiently convert a pre-designed Takagi-Sugeno fuzzy model-based analog controller into a sampled-data one in the sense of state matching. A delta operator is used to get an asymptotic relation between the analog and the sampled-data control systems. The IDR problem is viewed as a minimization problem of the norm distances between linear operator to be matched. The condition is represented as linear matrix inequalities, and the separation principle on the IDR is shown.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.5
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• pp.487-492
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• 2007

This paper presents the development of digital robust fuzzy controller for uncertain nonlinear systems. The proposed approach is based on the intelligent digital redesign(IDR) method with considering the relaxed stability condition of fuzzy control system. The term IDR in the concerned system is to convert an existing analog robust control into an equivalent digital counterpart in the sense of the state-matching. We shows that the IDR problem can be reduced to find the digital fuzzy gains minimizing the norm distance between the closed-loop states of the analog and digital robust control systems. Its constructive conditions are expressed as the linear matrix inequalities(LMIs) and thereby easily tractable by the convex optimization techniques. Based on the nonquadratic Lyapunov function, the robust stabilization conditions are given for the sampled-data fuzzy system, and hence less conservative. A numerical example, chaotic Lorentz system, is demonstrated to visualize the feasibility of the proposed methodology.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.5
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• pp.520-525
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• 2003

This paper concerns a design methodology of observer-based output-feedback digital controller for Takagi-Sugeno(TS) fuzzy systems using intelligent digital redesign (IDR). The term of IDR involves converting an analog fuzzy-mode-based controller into an equivalent digital one in the sense of state-matching. The considered IDR problem is viewed as convex minimization problems of the norm distances between linear operators to be matched. The stability condition is easily embedded and the separations principle is explicitly shown.

• Structural Engineering and Mechanics
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• v.72 no.3
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• pp.395-408
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• 2019

Engineered structures built in seismic-prone areas are affected by aftershocks in addition to mainshocks. Although aftershocks generally are lower in magnitude than that of the mainshocks, some aftershocks may have higher intensities; thus, structures should be able to withstand the effect of strong aftershocks as well. This seismic scenario arises for far-field mainshock along with near-field aftershocks. In this study, four 2D reinforced concrete (RC) frames with different numbers of stories were designed in accordance with the current Iranian seismic design code. As a way to evaluate the seismic response of the case-study RC frames, the inter-story drift ratio (IDR) demand, the residual inter-story drift ratio (RIDR) demand, the Park-Ang damage index, and the period elongation ratio can be useful engineering demand parameters for evaluating their seismic performance under mainshock-aftershock sequences. The frame models were analyzed under a set of far-field mainshock, near-fault aftershocks seismic sequences using nonlinear dynamic time-history analysis to investigate the relationship among IDR, RIDR, Park-Ang damage index and period ratio experienced by the frames. The results indicate that the growth of IDR, RIDR, Park-Ang damage index, and period ratio in high-rise and short structures under near-fault aftershocks were significant. It is evident that engineers should consider the effects of near-fault aftershocks on damaged frames that experience far-field mainshocks as well.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.7
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• pp.121-127
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• 2021

This study investigates the impact of the COVID-19 pandemic on exchange rates of the top ten currencies according to their trading value with Thailand by employing a regression analysis. Data includes daily number of COVID-19 cases - confirmed, new, deaths - and exchange rates against Thai Baht - CNY, JPY, USD, MYR, SGD, VND, IDR, AUD, HKD, TWD - which cover the period from January 2, 2020 to December 15, 2020. Results show that the confirmed cases of COVID-19 in Thailand relate to changes in all exchange rates; CNY, MYR, SGD, VND, AUD, and TWD have depreciated in relation to the THB, whereas JPY, USD, IDR, and HKD have appreciated. Furthermore, the new cases and deaths of COVID-19 have similar associations with almost all exchange rates. Deprecation of the JPY, USD, VND, HKD, and TWD in relation to the THB is due to new cases, on the contrary the MYR, IDR, and AUD have appreciated. Likewise, the JPY, USD, VND, and HKD have depreciated, but the CNY, MYR, SGD, and AUD have appreciated in relation to the THB owing to deaths cases. The study findings provide useful knowledge to manage an exchange rate risk for business and could help policymakers to improve the efficiency of exchange rate.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.11a
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• pp.91-94
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• 2005

This paper presents a new linear- matrix- inequality- basedintelligent digital redesign (LMI-based IDR) technique to match he states of the analog and the digital control systems at the intersampling instants as well as the sampling ones. The main features of the proposed technique are: 1) the multirate control is employed, and the control input is changed N times during one sampling period; 2) The proposed IDR technique is based on the compensated bilinear transformation.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2480-2482
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• 2005

This paper presents a complete solution to intelligent digital redesign problem (IDR) for sampled-data fuzzy systems. The IDR problem is the problem of designing a sampled-data state feedback controller such that the sampled-data fuzzy system is equivalent to the continuous-time fuzzy system in the sense of the state matching. Its solution is simply obtained by linear transformation. Under the proposed sampled-data controller, the states of the discrete-time model of the sampled-data fuzzy system completely matches the state of the discrete-time model of the closed-loop continuous-time fuzzy systems are completely matched at every sampling points.