Comparative assessment of a quasi-sequential and a sequential approach for distribution network stochastic analysis

2017 ◽  
Vol 2017 (1) ◽  
pp. 2161-2164 ◽  
Author(s):  
Martin Hupez ◽  
Zacharie De Grève ◽  
François Vallée
2021 ◽  
Author(s):  
POOJITHA S. N ◽  
Vinayakam Jothiprakash ◽  
B. Sivakumar

Abstract The design of a water distribution network (WDN) is an ever-challenging problem. Development and application of optimization techniques for WDN design have been an important area of research. Recently, the introduction of chaos theory-based evolutionary algorithms (EAs) in addition to traditional random-based ones has elevated the scope for further improving the performance of EAs. The present study proposes a chaos-directed genetic algorithm (CDGA) by incorporating chaos ergodicity in GA mechanics for WDN optimal design. Two novel frameworks, the non-sequential approach (NSA) and sequential approach (SA) are introduced. The influence of chaotic systems with high dimensionality maps in improving the search efficacy of GA when compared to the low dimensionality maps is explored. Considering four widely studied WDN benchmark problems, the performance of the proposed GA and CDGA models is evaluated. From the results, it is observed that the CDGA models outperform GA with better search efficacy, requiring fewer function evaluations to locate the optimal solution. Also, concerning the different chaotic maps used in the present study to induce chaos ergodicity, the results highlight the usefulness of chaos-directed search in improving the computational efficiency of GA. From the computational results, the study suggests the usage of a chaotic system with other bio-inspired techniques for their improved search and computational efficiency.


Author(s):  
ESMAEIL SHOJA ◽  
MOHAMMAD HASSAN CHERAGHALI ◽  
ALIREZA REZGHI ROSTAMI ◽  
ALIREZA DERAKHSHANI

Resilience as a counterpoint to vulnerability can reduce the vulnerability of various natural, man-made, and technological threats in complex technical systems. The present study was designed and conducted with the aim of comparative assessment of the vulnerability of a gas supply network to natural and technological threats. This descriptive-analytical and cross-sectional study was carried out in Tehran metropolis gas supply network including town board stations, gas supply, and distribution networks in 2019-2020. The study was based on the vulnerability analysis method including three factors of likelihood, severity of consequences, and the degree of preparedness for threats. Comparative vulnerability assessment in these three sections of the gas supply network was performed using IBM SPSS software v. 23.0. Out of eleven identified hazardous elements, the vulnerability index for three hazardous elements was estimated as a weak level threat; four hazardous elements as a medium level threat and the vulnerability index for four hazards were evaluated as a severe threat. The results of comparative vulnerability assessment based on three parts of gas supply network showed that the highest vulnerabilities related to the gas distribution network (133.66±24.63), gas supply network (115.0±35.35), and town board stations (79.49±68.51. In addition, the results of Kruskal-Wallis test showed that the vulnerability difference in these three sections was not significant (p>0.05). The findings of the comparative assessment of vulnerability between   different parts of the gas supply network including town board stations (TBS), gas supply and distribution network indicated that the resilience of these parts is relatively low and requires special attention in order to reduce vulnerability in Tehran metropolis gas supply network.


JAMA ◽  
1966 ◽  
Vol 197 (12) ◽  
pp. 943-948 ◽  
Author(s):  
E. T. Tyler

2020 ◽  
Vol 29 (12) ◽  
pp. 59-63
Author(s):  
O.I. Parakhina ◽  
◽  
M.N. Lokachuk ◽  
L.I. Kuznetsova ◽  
E.N. Pavlovskaya ◽  
...  

The research was carried out within the framework of the theme of state assignment № 0593–2019–0008 «To develop theoretical foundations for creating composite mixtures for bakery products using physical methods of exposure that ensure homogeneity, stability of mixtures and bioavailability of nutrients, to optimize diets population of Russia». The data on the species belonging of new strains of lactic acid bacteria and yeast isolated from samples of good quality gluten-free starter cultures are presented. A comparative assessment of the antagonistic and acid-forming activity of strains of lactic acid bacteria and the fermentative activity of yeast was carried out. The composition of microbial compositions from selected strains of LAB and yeast was developed. The influence of the starter culture on the new microbial composition on the physicochemical, organoleptic indicators of the bread quality and resistance to mold and ropy-disease was investigated.


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