• Title/Summary/Keyword: SGA

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[ $H_{\infty}$ ] Control for a Class of Singularly Perturbed Nonlinear Systems via Successive Galerkin Approximation

  • Kim, Young-Joong;Lim, Myo-Taeg
    • International Journal of Control, Automation, and Systems
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    • v.5 no.5
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    • pp.501-507
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    • 2007
  • This paper presents a new algorithm for the closed-loop $H_{\infty}$ control of a class of singularly perturbed nonlinear systems with an exogenous disturbance, using the successive Galerkin approximation (SGA). The singularly perturbed nonlinear system is decomposed into two subsystems of a slow-time scale and a fast-time scale in the spirit of the general theory of singular perturbation. Two $H_{\infty}$ control laws are obtained to each subsystem by using the SGA method. The composite control law that consists of two $H_{\infty}$ control laws of each subsystem is designed. One of the purposes of this paper is to design the closed-loop $H_{\infty}$ composite control law for the singularly perturbed nonlinear systems via the SGA method. The other is to reduce the computational complexity when the SGA method is applied to the high order systems.

Schema Analysis on Co-Evolutionary Algorithm (공진화 알고리즘에 있어서 스키마 해석)

  • Kwee-Bo Sim;Hyo-Byung Jun
    • Journal of Institute of Control, Robotics and Systems
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    • v.4 no.5
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    • pp.616-623
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    • 1998
  • Holland가 제안한 단순 유전자 알고리즘은 다원의 자연선택설을 기본으로 한 군 기반의 최적화 방법으로서, 이론적 기반으로는 스키마 정리와 빌딩블록 가설이 있다. 단순 유전자 알고리즘(SGA)이 이러한 이론적 기반에도 불구하고 여전히 일부 문제에 있어서 최적해로의 수렴을 보장하지 못하고 있다. 따라서 최근에 두 개의 집단이 서로 상호작용을 하며 진화하는 공진화 방법에 의해 이러한 문제를 해결하려고 하는데 많은 관심이 모아지고 있다. 본 논문에서는 이러한 공진화 방법이 잘 동작하는지에 대한 이론적 기반으로 확장 스키마 정리를 제안하고, SGA에서는 해결하지 못하는 최적화 문제, 예를 들면 deceptive function,에서 SGA와 공진화에 의한 방법을 비교함으로써 확장된 스키마 정리의 유효성을 확인한다.

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Isolation and Characterization of the Mutants in the Genes Involved in Mating Pheromone Signalling (효모의 mating pheromone 신호전달과정에 관여하는 유전자의 돌연변이 분리 및 분석)

  • Kim, Ji-Hye;Kim, Hwan-Gyu;Jahng, Kwang-Yeop
    • The Korean Journal of Mycology
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    • v.19 no.4
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    • pp.266-275
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    • 1991
  • The gene CDC70 encoding the${\alpha}-subunit$ of G protein has been known to be a component involved in mating pheromone signalling in the yeast, Saccharomyces cerevisiae. To isolate mutations of the genes involved in the signal transduction, Saccharomyces cerevisiae the strain bearing the cdc70-5 mutation was mutagenized to be forced to recover the ability of colony-formation at restrictive temperature, which means the new mutation can suppress the temperature sensitivity of the cdc70-5 phenotypes. Among these suppressors, $sir^-$ and $mat{\alpha}2^{-}$ mutations are excluded because of no relationship to signal transducer. And the selected suppressors were analyzed for the linkage relationships by the tetrad analysis. Out of fifteen suppressors isolated, twelve were classified into four linkage groups, designated as sga1, sga2, sga3, sga4 by the tetrad analysis. The other three genes were determined for the linkage.

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A Study on the Right of the Suspension of Performance under SGA (SGA상의 이행정지권에 관한 연구)

  • Min, Joo-Hee
    • Korea Trade Review
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    • v.41 no.5
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    • pp.187-211
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    • 2016
  • This study discusses the right of suspension of performance against anticipatory breach under SGA. Anticipatory breach originated in Hochster v De La Tour allows the innocent party to exercise immediately the right or rights reserved for the non-performance of obligations. But it has not been codified in English Law. Instead, under SGA s. 41 and s. 44, the seller may suspend his performance against the buyer' anticipatory breach. Lien under s. 41 and stoppage in transit under s. 44 are given only to the seller in a narrowly-defined situation. Under SGA s. 41, the unpaid seller is entitled to retain possession of goods where the buyer becomes insolvent. But under SGA s. 43, the unpaid seller loses the right of lien when he delivers goods to a carrier or other bailee or custodian for the purpose of transmission to the buyer without reserving the right of disposal, or when the buyer or his agent lawfully obtains possession of the goods, or by waiver of lien. Under SGA s. 44, the unpaid seller may exercise the right of stoppage in transit if the buyer becomes insolvent, despite the fact that the property of goods has passed or a bill of lading has been transferred to the buyer. But, under s. 45, the right of stoppage in transit is ended when the buyer or his agent takes delivery of goods. And where the buyer transfers a bill of lading to a sub-buyer, the unpaid seller loses his right to stop goods in transit.

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Validation of initial nutrition screening tool for hospitalized patients (입원 환자용 초기 영양검색도구의 타당도 검증)

  • Kim, Hye-Suk;Lee, Seonheui;Kim, Hyesook;Kwon, Oran
    • Journal of Nutrition and Health
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    • v.52 no.4
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    • pp.332-341
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    • 2019
  • Purpose: Poor nutrition in hospitalized patients is closely linked to an increased risk of infection, which can result in complications affecting mortality, as well as increased length of hospital stay and hospital costs. Therefore, adequate nutritional support is essential to manage the nutritional risk status of patients. Nutritional support needs to be preceded by nutrition screening, in which accuracy is crucial, particularly for the initial screening. To perform initial nutrition screening of hospitalized patients, we used the Catholic Kwandong University (CKU) Nutritional Risk Screening (CKUNRS) tool, originally developed at CKU Hospital. To validate CKUNRS against the Patient-Generated Subjective Global Assessment (PG-SGA) tool, which is considered the gold standard for nutritional risk screening, results from both tools were compared. Methods: Nutritional status was evaluated in 686 adult patients admitted to CKU Hospital from May 1 to July 31, 2018 using both CKUNRS and PG-SGA. Collected data were analyzed, and the results compared, to validate CKUNRS as a nutrition screening tool. Results: The comparison of CKUNRS and PG-SGA revealed that the prevalence of nutritional risk on admission was 15.6% (n = 107) with CKUNRS and 44.6% (n = 306) with PG-SGA. The sensitivity and specificity of CKUNRS to evaluate nutritional risk status were 98.7% (96.8 ~ 99.5) and 33.3% (28.1 ~ 39.0), respectively. Thus, the sensitivity was higher, but the specificity lower compared with PG-SGA. Cohen's kappa coefficient was 0.34, indicating valid agreement between the two tools. Conclusion: This study found concordance between CKUNRS and PG-SGA. However, the prevalence of nutritional risk in hospitalized patients was higher when determined by CKUNRS, compared with that by PG-SGA. Accordingly, CKUNRS needs further modification and improvement in terms of screening criteria to promote more effective nutritional support for patients who have been admitted for inpatient care.

Parallel Robust $H_{\infty}$ Control for Weakly Coupled Bilinear Systems with Parameter Uncertainties Using Successive Galerkin Approximation

  • Kim, Young-Joong;Lim, Myo-Taeg
    • International Journal of Control, Automation, and Systems
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    • v.4 no.6
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    • pp.689-696
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    • 2006
  • This paper presents a new algorithm for the closed-loop $H_{\infty}$ composite control of weakly coupled bilinear systems with time-varying parameter uncertainties and exogenous disturbance using the successive Galerkin approximation(SGA). By using weak coupling theory, the robust $H_{\infty}$ control can be obtained from two reduced-order robust $H_{\infty}$ control problems in parallel. The $H_{\infty}$ control theory guarantees robust closed-loop performance but the resulting problem is difficult to solve for uncertain bilinear systems. In order to overcome the difficulties inherent in the $H_{\infty}$ control problem, two $H_{\infty}$ control laws are constructed in terms of the approximated solution to two independent Hamilton-Jacobi-Isaac equations using the SGA method. One of the purposes of this paper is to design a closed-loop parallel robust $H_{\infty}$ control law for the weakly coupled bilinear systems with parameter uncertainties using the SGA method. The other is to reduce the computational complexity when the SGA method is applied to the high order systems.

$H_{\infty}$ Composite Control for Singularly Perturbed Nonlinear Systems via Successive Galerkin Approximation

  • Kim, Young-Joong;Kim, Beom-Soo;Shin, Eun-Chul;Yoo, Ji-Yoon;Lim, Myo-Taeg
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.407-412
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    • 2004
  • This paper presents a new algorithm for the closed-loop $H_{\infty}$ composite control of singularly perturbed nonlinear systems with a exogenous disturbance, using the successive Galerkin approximation(SGA). The singularly perturbed nonlinear system is decomposed into two subsystems of a slow-time scale and a fast-time scale via singular perturbation theory, and two $H_{\infty}$ control laws are obtained to each subsystem by using the SGA method. The composite control law that consists of two $H_{\infty}$ control laws of each subsystem is designed. One of the purposes of this paper is to design the closed-loop $H_{\infty}$ composite control law for the singularly perturbed nonlinear systems via the SGA method. The other is to reduce the computational complexity when the SGA method is applied to the high order systems.

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Evaluation of Nutritional Status of Inpatients with Medical Health Problems (내과 입원환자의 초기 영양상태 평가)

  • Hwang, Eun-Sook;Kim, Ju-Sung;Shin, Jae-Shin
    • The Korean Journal of Rehabilitation Nursing
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    • v.6 no.1
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    • pp.14-25
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    • 2003
  • Purpose: To investigate nutritional status of inpatients by using subjective, and objective evaluation methods and to find the relationship between them. Method: The subjects were 101 inpatients with medical health problems at a university hospital. Nutritional status was evaluated by the Subjective Global Assessment(SGA) and physical assessment including percentage of weight loss, serum albumin, hemogloin, and hematocrit. Data were analyzed using frequency, percentage, mean, Kendall's tau. Results: Grouping by the SGA, 61.4% were classified as severe malnutrition group. When applying the objective methods(physical assessment), 1.9~42.6% were diagnosed as malnutrition each item. The percentage of weight loss during previous 1~6month(${\tau}=.43{\sim}.54$, P=.0001), serum albumin(${\tau}=-.26$, P=.0003), hemoglobin of male(${\tau}=-.38$, P=.0001), and hematocrit of male(${\tau}=-.34$, P=.0001) were significantly correlated with SGA score. The coincidence rate of nutrition evaluation between the objective methods and SGA were 27.7~35.6%, 20.8%, 47.5%, 58.4% in percentage of weight loss, albumin, hemoglobin, and hematocrit. Conclusion: These findings showed a majority of inpatients were exposed to the risk of malnutrition. We recommend to evaluate inpatients' nutritional status periodically and to develop nursing intervention to solve their nutritional problems.

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Efficacy and safety of growth hormone treatment for children born small for gestational age

  • Hwang, Il Tae
    • Clinical and Experimental Pediatrics
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    • v.57 no.9
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    • pp.379-383
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    • 2014
  • Recombinant growth hormone (GH) is an effective treatment for short children who are born small for gestational age (SGA). Short children born SGA who fail to demonstrate catch-up growth by 2-4 years of age are candidates for GH treatment initiated to achieve catch-up growth to a normal height in early childhood, maintain a normal height gain throughout childhood, and achieve an adult height within the normal target range. GH treatment at a dose of $35-70{\mu}g/kg/day$ should be considered for those with very marked growth retardation, as these patients require rapid catch-up growth. Factors associated with response to GH treatment during the initial 2-3 years of therapy include age and height standard deviation scores at the start of therapy, midparental height, and GH dose. Adverse events due to GH treatment are no more common in the SGA population than in other conditions treated with GH. Early surveillance in growth clinics is strongly recommended for children born SGA who have not caught up. Although high dose of up to 0.067 mg/kg/day are relatively safe for short children with growth failure, clinicians need to remain aware of long-term mortality and morbidity after GH treatment.

A study on the nonlinearity in bio-logical systems using approximate entropy and correlation dimension (근사엔트로피와 상관차원을 이용한 비선형 신호의 분석)

  • Lee, Hae-Jin;Choi, Won-Young;Cha, Kyung-Joon;Park, Moon-Il;Oh, Jae-Eung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.760-763
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    • 2007
  • We studied how linear and nonlinear heart rate dynamics differ between normal fetuses and uncomplicated small-forgestational age (SGA) fetuses, aged 32-40 weeks' gestation. We analyzed each fetal heart rate time series for 20 min and quantified the complexity (nonlinear dynamics) of each fetal heart rate (FHR) time series by approximate entropy (ApEn) and correlation dimension (CD). The linear dynamics were analyzed by canonical correlation analysis (CCA). The ApEn and CD of the uncomplicated SGA fetuses were significantly lower than that of the normal fetuses in all three gestational periods (32-34, 35-37, 38-40 weeks). Canonical correlation ensemble in SGA fetuses is slightly higher than normal ones in all three gestational periods, especially at 35-37 weeks. Irregularity and complexity of the heart rate dynamics of SGA fetuses are lower than that of normal ones. Also, canonical ensemble in SGA fetuses is higher than in normal ones, suggesting that the FHR control system has multiple complex interactions. Along with the clear difference between the two groups' non-linear chaotic dynamics in FHR patterns, we clarified the hidden subtle differences in linearity (e.g. canonical ensemble). The decrease in non-linear dynamics may contribute to the increase in linear dynamics. The present statistical methodology can be readily and routinely utilized in Obstetrics and Gynecologic fields.

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