• Title/Summary/Keyword: selection pressure

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An Input Feature Selection Method Applied to Fuzzy Neural Networks for Signal Estimation

  • Na, Man-Gyun;Sim, Young-Rok
    • Nuclear Engineering and Technology
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    • v.33 no.5
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    • pp.457-467
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    • 2001
  • It is well known that the performance of a fuzzy neural network strongly depends on the input features selected for its training. In its applications to sensor signal estimation, there are a large number of input variables related with an output As the number of input variables increases, the training time of fuzzy neural networks required increases exponentially. Thus, it is essential to reduce the number of inputs to a fuzzy neural network and to select the optimum number of mutually independent inputs that are able to clearly define the input-output mapping. In this work, principal component analysis (PCA), genetic algorithms (CA) and probability theory are combined to select new important input features. A proposed feature selection method is applied to the signal estimation of the steam generator water level, the hot-leg flowrate, the pressurizer water level and the pressurizer pressure sensors in pressurized water reactors and compared with other input feature selection methods.

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Research On The Relevance Between Mixed-use Complex and User Behaviour Based On Three-dimensional Spatial Analysis

  • Zhendong Wang;Yihan Pan;Yi Lu;Xihui Zhou
    • International Journal of High-Rise Buildings
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    • v.12 no.1
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    • pp.83-91
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    • 2023
  • Under the dual pressure of population growth and land shortage, threedimensional development is the inevitable choice for cities in China. In such a scenario, a mixed-use complex has considerable potential in its realization and research. Based on space syntax and the three-dimensional visibility graph analysis, this paper describes the spatial and functional layout of the Shanghai Super Brand Mall and studies the relationship between spatial visibility and user behaviour through linear regression analysis and correlation analysis. This paper studies three different types of user behaviour, namely, path selection, staying selection, and store selection, and finds that spatial visibility and accessibility have different effects on user behaviour depending on the type and purpose of the activity. This paper reveals the influence of spatial and functional layout on user behaviour and puts forward the corresponding design strategy under the three-dimensional environment.

Effect of air flow channel configuration on performance of direct methanol fuel cells. (공기극 채널 형상이 직접 메탄올 연료전지의 성능에 미치는 영향)

  • Hwang, Yong-Sheen;Choi, Hoon;Cha, Suk-Won;Lee, Dae-Young;Kim, Seo-Young
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.137-140
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    • 2007
  • We consider the optimum air flow channel design for DMFC's in the present study. The effect of pressure drop across the inlet and outlet of a stack on the performance of a DMFC is the optimization of such geometric parameters is crucial to minimize the parasitic power usage by the auxiliary devices such as fuel pumps and blowers. In this paper, we present how the pressure drop control can optimize the driving point of a DMFC stack. Further, we show how the optimal fuel utilization ratio can be achieved, not degrading the performance of DMFC stacks. Overall, we discuss how the flow channel design affects the selection of balance of plant(BOP) components, the design of DMFC systems and the system efficiency.

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Development of the Numerical Model for Temperature Prediction of Fruits (청과물의 품온예측모델 개발)

  • 김의웅;김병삼;남궁배;정진웅;김동철;금동혁
    • Journal of Biosystems Engineering
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    • v.20 no.4
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    • pp.343-350
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    • 1995
  • In order to design efficient and effective pressure cooling system for fruits and vegetables, a numerical model for temperature prediction of fruits was developed. This model was extended to study the various factors affecting product cooling time, such as product depth, approach air temperature, entering air velocity and initial product temperature. Also, selection of these factors were examined with respect to the efficiency of the pressure cooling system, the overall precooling cost and the final quality of the product. When designing a pressure cooling system for a particular product, the range of the factors must be selected carefully according to the thermal and physiological properties.

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Effect of System Configuration on Design Performance of Atmospheric Pressure MCFC/Gas Turbine Hybrid Systems (상압형 MCFC/가스터빈 하이브리드 시스템의 구성방법에 따른 설계성능 분석)

  • Oh Kyong Sok;Kim Tong Seop
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.11
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    • pp.1021-1027
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    • 2004
  • Design performances of various configurations of hybrid systems combining an atmospheric pressure molten carbonate fuel cell and a gas turbine have been analyzed. Two different fuel reforming methods (internal and external reforming) were considered. Influences of turbine inflow heating method, location of fuel combustor and associated component arrangements were investigated. In general, internal reforming leads to higher system efficiencies. The optimum design pressure ratio varies among different system configurations. In particular, the design point selection is closely related to the allowable turbine inlet temperature. Configurations with direct heating of turbine inlet flow may realize both higher efficiency and higher specific power than those with indirect heating.

Improved first-order method for estimating extreme wind pressure considering directionality for non-typhoon climates

  • Wang, Jingcheng;Quan, Yong;Gu, Ming
    • Wind and Structures
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    • v.31 no.5
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    • pp.473-482
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    • 2020
  • The first-order method for estimating the extreme wind pressure on building envelopes with consideration of the directionality of wind speed and wind pressure is improved to enhance its computational efficiency. In this improved method, the result is obtained directly from the empirical distribution of a random selection of annual maximum wind pressure samples generated by a Monte Carlo method, rather than from the previously utilized extreme wind pressure probability distribution. A discussion of the relationship between the first- and full-order methods indicates that when extreme wind pressures in a non-typhoon climate with a high return period are estimated with consideration of directionality, using the relatively simple first-order method instead of the computationally intensive full-order method is reasonable. The validation of this reasonableness is equivalent to validating two assumptions to improve its computational efficiency: 1) The result obtained by the full-order method is conservative when the extreme wind pressure events among different sectors are independent. 2) The result obtained by the first-order method for a high return period is not significantly affected when the extreme wind speeds among the different sectors are assumed to be independent. These two assumptions are validated by examples in different regions and theoretical derivation.

A New Selection System for Pepper Regeneration by Mannose

  • Kim, Joo-Yean;Min Jung;Kim, Hyo-Soon;Lee, Yun-Hee;Park, Soon-Ho;Lim, Yong-Pyo;Min, Byung-Whan;Yang, Seung-Gyun;Harn, Chee-Hark
    • Journal of Plant Biotechnology
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    • v.4 no.3
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    • pp.129-134
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    • 2002
  • We report the development of a new selection system for the transformation of pepper plants by mannose. In order to achieve this, we first tested several factors related to regeneration conditions. Among the 30 inbred lines examined, line P9l5 was able to generate shoots at the highest rate from both cotyledons and hyporotyls in MS media. A dosage curve for optimizing the selection conditions was established by mixing mannose (range 0-50 g/L) and sucrose (range 0-30 g/L). The least selection pressure on shoot formation was created by a mixture of sucrose and mannose at 20 g/L and 15 g/L, respectively, and the threshold for ultimate tissue death was 50 g/L of mannose irrespective of the sucrose concentration. However, we found that mannose itself was not the sole inhibitor of pepper shoot development. High concentrations of sucrose (30 g/L) contributed additively to the inhibition of shoot formation at higher mannose concentrations. Genotype preference is a major factor that enhances regeneration ability in mannose media, as was observed in MS media. P9l5 and P410 line had high regeneration rates under mannose selection conditions in the presence of Agrobacterium infection. Different virulence levels of Agrobacterium strains did change the regeneration rates, probably due to interaction with the specificities of the inbred lines. Taken together, P9l5 offers the best pepper inbred line for transformation and we recommend a selection condition of 20 g/L of sucrose and 15 g/L or more of mannose up to 50 g/L in media.

Study on the selection of TBM in consideration of field conditions (시공여건을 반영한 TBM선정 방법에 대한 연구)

  • Oh, Joon-Geun;Sagong, Myung
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.16 no.2
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    • pp.125-133
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    • 2014
  • In this study, TBM selection methods to meet soil and site conditions were presented. Factors and excavation equipment affecting TBM selection by soil and environmental condition were selected and classified. Weights between equipment and influencing factors selected were calculated by applying the AHP (Analytic Hierarchy Process) method. The results of the analysis influence factors, Ground condition was a major factor in objective factors and strength was a major factor in the hard condition of criteria factors and water pressure was a major factor in the soft ground condition of criteria factors. In Environment condition, existence of adjacent structures was evaluated more important than existence of feasible site. Lastly, Adequacy was verified through the deduction of results that coincide with input equipment by applying derived weights to actual site conditions.

Low Levels of Polymorphisms and Negative Selection in Plasmodum knowlesi Merozoite Surface Protein 8 in Malaysian Isolates

  • Ahmed, Md Atique;Kang, Hae-Ji;Quan, Fu-Shi
    • Parasites, Hosts and Diseases
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    • v.57 no.4
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    • pp.445-450
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    • 2019
  • Human infections due to the monkey malaria parasite Plasmodium knowlesi is increasingly being reported from most Southeast Asian countries specifically Malaysia. The parasite causes severe and fatal malaria thus there is a need for urgent measures for its control. In this study, the level of polymorphisms, haplotypes and natural selection of full-length pkmsp8 in 37 clinical samples from Malaysian Borneo along with 6 lab-adapted strains were investigated. Low levels of polymorphism were observed across the full-length gene, the double epidermal growth factor (EGF) domains were mostly conserved, and non-synonymous substitutions were absent. Evidence of strong negative selection pressure in the non-EGF regions were found indicating functional constrains acting at different domains. Phylogenetic haplotype network analysis identified shared haplotypes and indicated geographical clustering of samples originating from Peninsular Malaysia and Malaysian Borneo. This is the first study to genetically characterize the full-length msp8 gene from clinical isolates of P. knowlesi from Malaysia; however, further functional characterization would be useful for future rational vaccine design.