• Title/Summary/Keyword: two component system

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Transcriptome Analysis of Phosphate Starvation Response in Escherichia coli

  • Baek, Jong-Hwan;Lee, Sang-Yup
    • Journal of Microbiology and Biotechnology
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    • v.17 no.2
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    • pp.244-252
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    • 2007
  • Escherichia coli has a PhoR-PhoB two-component regulatory system to detect and respond to the changes of environmental phosphate concentration. For the E. coli W3110 strain growing under phosphate-limiting condition, the changes of global gene expression levels were investigated by using DNA microarray analysis. The expression levels of some genes that are involved in phosphate metabolism were increased as phosphate became limited, whereas those of the genes involved in ribosomal protein or amino acid metabolism were decreased, owing to the stationary phase response. The upregulated genes could be divided into temporarily and permanently inducible genes by phosphate starvation. At the peak point showing the highest expression levels of the phoB and phoR genes under phosphate-limiting condition, the phoB- and/or phoR-dependent regulatory mechanisms were investigated in detail by comparing the gene expression levels among the wild-type and phoB and/or phoR mutant strains. Overall, the phoB mutation was epistatic over the phoR mutation. It was found that PhoBR and PhoB were responsible for the upregulation of the phosphonate or glycerol phosphate metabolism and high-affinity phosphate transport system, respectively. These results show the complex regulation by the PhoR-PhoB two-component regulatory system in E. coli.

Joint Batch Production and Inventory Rationing Control in a Two-Station Serial Production System (두 단계 일렬 생산 시스템에서 뱃치 생산과 재고 배급 전략의 통합 구현)

  • Kim, Eun-Gab
    • Journal of Korean Institute of Industrial Engineers
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    • v.38 no.2
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    • pp.89-97
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    • 2012
  • This paper considers a manufacturer with a two-station make-to-stock and make-to-order serial production system. The MTS facility produces a single type of component and provides components for the MTO facility that produces customized products. In addition to the internal demand from the MTO facility, the MTS facility faces demands from the spot market with the option of to accept or reject each incoming demand. This paper addresses a joint component inventory rationing and batch production control which maximizes the manufacturer's profit. Using the Markov decision process model, we investigate the structural properties of the optimal inventory rationing and batch production policy, and present two types of heuristics. We implement a numerical experiment to compare the performance of the optimal and heuristic policies and a simulation study to examine the impact of the stochastic process variability on the inventory rationing and batch production control.

Optimal System Burn-in for Maximizing Reliability of Non-series Systems (비 직렬 시스템의 신뢰도 최적화를 위한 시스템 번인)

  • Kim, Kyungmee O.
    • Journal of Korean Institute of Industrial Engineers
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    • v.33 no.2
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    • pp.273-281
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    • 2007
  • The decision of how long performing system burn-in must be answered with a probabilistic model of a system lifetime at which infant mortality failures created during assembly processes are quantified. In this paper, we propose such a model which is modified from previous results. Using the system model, we derived system reliability in terms of component and system burn-in times for the two cases of minimal repair at system failure and of component replacement and connection repair at their failure times. The procedure is illustrated with a bridge system and the optimal system burn-in times are obtained for maximizing system reliability. The result suggests that an assumption of minimal repair at system failure may underestimate the optimal burn-in time in practice.

A Comparative Study of Frequency Estimation Techniques using High Speed FIR Filter and Phasor Angle between Two Phasors (고속 FIR 필터와 두 페이저 위상을 이용한 주파수 추정 알고리즘의 비교 연구)

  • Park, Chul-Won
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.2
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    • pp.122-129
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    • 2009
  • Frequency is an important operating parameter of a power system. It is essential that the frequency of a power system be maintained very close to its nominal frequency. And frequency measurement devices have need to measure a fast and accurate of frequency using voltage signals. This paper proposes a comparative study of frequency estimation techniques using the high speed FIR filter based algorithm, the DFT filter based algorithm using phasor angle between two phasors, and positive sequence component based algorithm using the half angle between two successive positions of phasor. The discussed three techniques have been formed through numerical manipulation of a discrete system. The proposed techniques have been tested using signals obtained from selected power system model using ATP simulation package. Some test results are shown in this paper.

Fixed bed column modeling of lead(II) and cadmium(II) ions biosorption on sugarcane bagasse

  • Vera, Luisa Mayra;Bermejo, Daniel;Uguna, Maria Fernanda;Garcia, Nancy;Flores, Marittza;Gonzalez, Enrique
    • Environmental Engineering Research
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    • v.24 no.1
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    • pp.31-37
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    • 2019
  • In this paper the results of the biosorption of lead(II) and cadmium(II) with sugarcane bagasse in fixed bed columns are presented. Experimental data were fitted to several models describing the rupture curve for single-component and two-component systems. The percentages of removal of lead and cadmium in single-component systems are 91% and 90%, respectively. In lead-cadmium bicomponent systems the percentage of elimination of lead was 90% and cadmium 92%. In single-component systems, Yoon-Nelson and Thomas models successfully reproduce the rupture curves. In two-component system, the Dose-Response model was the best one reproducing the experimental rupture curves in the entire measured range.

Development of a special thermal-hydraulic component model for the core makeup tank

  • Kim, Min Gi;Wisudhaputra, Adnan;Lee, Jong-Hyuk;Kim, Kyungdoo;Park, Hyun-Sik;Jeong, Jae Jun
    • Nuclear Engineering and Technology
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    • v.54 no.5
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    • pp.1890-1901
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    • 2022
  • We have assessed the applicability of the thermal-hydraulic system analysis code, SPACE, to a small modular reactor called SMART. For the assessment, the experimental data from a scale-down integral-test facility, SMART-ITL, were used. It was conformed that the SPACE code unrealistically calculates the safety injection flow rate through the CMT and SIT during a small-break loss-of-coolant experiment. This unrealistic behavior was due to the overprediction of interfacial heat transfer at the steam-water interface in a vertically stratified flow in the tanks. In this study, a special thermal-hydraulic component model has been developed to realistically calculate the interfacial heat transfer when a strong non-equilibrium two-phase flow is formed in the CMT or SIT. Additionally, we developed a special heat structure model, which analytically calculates the heat transfer from the hot steam to the cold tank wall. The combination of two models for the tank are called the special component model. We assessed it using the SMART-ITL passive safety injection system (PSIS) test data. The results showed that the special component model well predicts the transient behaviors of the CMT and SIT.

Reliability of the redundant system with dependent human error (인간실수를 고려한 중복시스템의 신뢰도 분석)

  • 김명기;장순흥
    • Journal of the Ergonomics Society of Korea
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    • v.1 no.2
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    • pp.11-15
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    • 1982
  • There is the possibility that human error during testing and maintenance brings about the failure of the system, the reliability of which depends on mechanical failure and human error. This paper deals with the calculation of the reliability of the redundant system with the dependent hunman error through Karnaugh Map. Two cases are considered. One is the reli- ability of the system neglecting the test interval of each component and the other is that considering the test interval of each component.

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AN ESR STUDY OF AMINO ACID AND PROTEIN FREE RADICALS IN SOLUTION PART I. Reaction Mechanism of Free Radical Production in the Ti-$H_2O_2$ Flow System (용액에서의 아미노산 및 단백질 자유기에 관한 ESR 연구 제1보 ; Ti-$H_2O_2$ Flow System에서 자유기를 만드는 반응기구)

  • Hong Sun-Joo;L. H. Piette
    • Journal of the Korean Chemical Society
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    • v.15 no.1
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    • pp.37-44
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    • 1971
  • The reaction of amino acids and the reactive hydroxyl radical generated by $Ti^{3+}-H_2O_2$ system was studied using fast flow techniques coupled with ESR. Upon adding methionine to the 0.2M $H_2O_2$ solution (0.05M methionine after addition) and mixing with 0.01M $TiCl_3$, the low field component of the two incompletely resolved peaks, in the spectrum of $Ti^{3+}-H_2O_2$ system alone, vanished completely whereas the high field component remained almost constant and superimposed on the secondary spectrum of the methionine free radical. Similar results were obtained for other amino acids and proteins. The results strongly demonstrate that the $T^{3+}-H_2O_2$ flow system generates two different radical species, only one of which, giving rise to the low field component, is alone responsible for abstracting hydrogen atoms from substrate molecules. The effects of HCl, $H_2SO_4$ and NaOH on the system were also studied with widely varying results.

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Estimation of Reliability for a Two-Component Shared Parallel Systems Using System Life Data (체계수명자료를 이용한 이중부품부하분배체계의 신뢰도 추정)

  • 홍연웅;권용만
    • Journal of Korean Society for Quality Management
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    • v.25 no.4
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    • pp.206-212
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    • 1997
  • This paper considers the problem of estimating parameters and reliability of shared parallel system with two identical components using type II censored system life data. Likelihood functions are derived and maximum likelihood estimates of parameters and reliability are discussed numerically.

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A Two-Phase Component Identification Method using Static and Dynamic Relationship between Classes (클래스들 간의 정적ㆍ동적 관계에 의한 2단계 컴포넌트 식별방법)

  • Choi Mi-Sook;Cho Eun-Sook;Park Jai-Nyun;Ha Jong-Sung
    • Journal of KIISE:Computing Practices and Letters
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    • v.11 no.1
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    • pp.1-14
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    • 2005
  • It is difficult to identify reusable and independent components in component-based development(CBD) process. Therefore existing methodologies have dealt the problem of component identification based on only developer's intuition and heuristics. As a result, it is difficult to identify the business components by common developers. Therefore, in this paper, we propose a new baseline and technique to identify the business components based on domain model such as use case diagrams, class diagrams, and sequence diagrams. proposed method identifies components through two phases; system component identification and business component identification. Especially, we consider structural characteristics as well as dependency characteristics according to methods call types and directions in identifying components. We also present a case study and comparative analysis and assessment to prove the practical use of our technique.