An improved nondominated sorting genetic algorithm-II (INSGA-II) has been proposed for optimal planning of multiple distributed generation (DG) units in this paper. First, multiobjective functions ...that take minimum line loss, minimum voltage deviation, and maximal voltage stability margin into consideration have been formed. Then, using the proposed INSGA-II algorithm to solve the multiobjective planning problem has been described in detail. The improved sorting strategy and the novel truncation strategy based on hierarchical agglomerative clustering are utilized to keep the diversity of population. In order to strengthen the global optimal searching capability, the mutation and recombination strategies in differential evolution are introduced to replace the original one. In addition, a tradeoff method based on fuzzy set theory is used to obtain the best compromise solution from the Pareto-optimal set. Finally, several experiments have been made on the IEEE 33-bus test case and multiple actual test cases with the consideration of multiple DG units. The feasibility and effectiveness of the proposed algorithm for optimal placement and sizing of DG in distribution systems have been proved.
Schemes of reversible data hiding in encrypted domain (RDH-ED) based on symmetric or public key encryption are mainly applied in the scenarios of end-to-end communication. To provide security ...guarantees for the multi-party scenarios, a RDH-ED scheme for secret image sharing based on Chinese remainder theorem (CRT) is presented. In the application of (<inline-formula> <tex-math notation="LaTeX">t </tex-math></inline-formula>, <inline-formula> <tex-math notation="LaTeX">n </tex-math></inline-formula>) secret image sharing, an image is first shared into <inline-formula> <tex-math notation="LaTeX">n </tex-math></inline-formula> different shares of ciphertext. Only when not less than <inline-formula> <tex-math notation="LaTeX">t </tex-math></inline-formula> shares obtained, can the image be reconstructed. In our scheme, additional data could be embedded into the image shares. To realize data extraction from the image shares and the reconstructed image separably, two data hiding methods are proposed: one is homomorphic difference expansion in encrypted domain (HDE-ED) that supports data extraction from the reconstructed image by utilizing the addition homomorphism of CRT secret sharing; the other is difference expansion in image shares (DE-IS) that supports the data extraction from the marked shares before image reconstruction. Experimental results demonstrate that the proposed scheme could not only maintain the security and the threshold function of secret sharing system, but also obtain a better reversibility and efficiency compared with most existing RDH-ED algorithms. The maximum embedding rate of HDE-ED could reach 0.500 bits per pixel and the average embedding rate of DE-IS could reach 0.4652 bits per pixel.
Emergence of dysmorphic neurons is the primary pathology in focal cortical dysplasia (FCD) associated pediatric intractable epilepsy; however, the etiologies related to the development and function ...of dysmorphic neurons are not fully understood. Our previous studies revealed that the expression of vascular endothelial growth factor‐C (VEGF‐C) and corresponding receptors VEGFR‐2, VEGFR‐3 was increased in the epileptic lesions of patients with tuberous sclerosis complex or mesial temporal lobe epilepsy. Here, we showed that the expression of VEGF‐C, VEGFR‐2, and VEGFR‐3 was increased at both mRNA and protein levels in patients with cortical lesions of type I, IIa, and IIb FCD. The immunoreactivity of VEGF‐C, VEGFR‐2 and VEGFR‐3 was located in the micro‐columnar neurons in FCD type I lesions, dysplastic neurons (DNs) in FCD type IIa lesions, balloon cells (BCs) and astrocytes in FCD type IIb lesions. Additionally, the amplitude of evoked‐EPSCs (eEPSC) mediated by NMDA receptor, the ratio of NMDA receptor‐ and AMPA receptor‐mediated eEPSC were increased in the dysmorphic neurons of FCD rats established by prenatal X‐ray radiation. Furthermore, NMDA receptor mediated current in dysmorphic neurons was further potentiated by exogenous administration of VEGF‐C, however, could be antagonized by ki8751, the blocker of VEGFR‐2. These results suggest that VEGF‐C system participate in the pathogenesis of cortical lesions in patients with FCD in association with modulating NMDA receptor–mediated currents.
Shen et al. demonstrate that the expression of VEGF‐C system is increased in the cortical lesions of young patients and rat models with FCD, and participates the epileptogenicity of FCD by modulating NMDA receptor mediated currents.
•Multi-objective optimization in DG planning.•Time sequence characteristics of loads and DGs.•Wind turbine generation and Photovoltaic combination.•Improved Non-dominated Sorting Genetic Algorithm ...II.
With the consideration of time sequence characteristics of load and distributed generator (DG) output, a novel method is presented for optimal sitting and sizing of DG in distributed system. Multi-objective functions have been formulated with the consideration of minimum investment and operational cost of DG, minimum purchasing electricity cost from main grid and minimum voltage deviation. To solve the multi-objective optimization problem, an improved Non-dominated Sorting Genetic Algorithm II has been proposed. The compromised solution is extracted from the Pareto set using the fuzzy theory method. Several experiments have been made on the modified PG&E 69-bus and multiple actual test cases with the consideration of multiple DGs. The computational result and comparisons indicate the proposed method for optimal placement and sizing of DG is feasible and effective.
Altitudinal diversity of terrestrial plants has been widely studied, whereas little is known for the patterns of aquatic plants. Here, we used a standardised field dataset to quantify the altitudinal ...patterns in the diversity and structure of aquatic plant assemblages, as well as the relationships between diversity indices and environmental variables.
Large‐scale field investigations were carried out in 128 sites ranging from 2,280 to 5,020 m above sea level across the southern part of Qinghai‐Tibet Plateau, China. In total, 102 species of aquatic plants were recorded, belonging to 67 genera, 31 families. Five taxonomic, phylogenetic, and functional indices were calculated for each collection site. We firstly examined altitudinal patterns of these diversity indices, then quantified the variations of indices across water areas, water flow, and soil matrix, respectively. We also explored the relationships between diversity indices and environmental variables using redundancy and variance partitioning analysis, to detect the ecological variables that drove the diversity.
The results showed that taxonomic, phylogenetic, and functional diversity of aquatic plants decreased with increasing altitude. Net relatedness index of aquatic plants showed a hump pattern along the altitude gradient, with a peak around 3,800 m above sea level. There was no obvious trend in the net functional relatedness index of aquatic plants with altitude. Annual mean temperature was the most important variable associated with the taxonomic, phylogenetic, and functional diversity. Water area and water flow were significantly associated with functional structure, but not phylogenetic structure. Soil matrix also correlated with aquatic plant diversity.
A large‐scale altitudinal gradient can influence aquatic plant diversity. Environmental filtering and niche convergence might have played dominant roles in the increasing and decreasing stages of phylogenetic structure of aquatic plant assemblages, respectively, along the altitudinal gradient. Phylogenetic and functional structure of aquatic plant assemblages showed different patterns along the altitudinal gradient, and the environmental variables better explained the change of functional structure than did the phylogenetic variables.
This is the first comprehensive study on the species, phylogeny, and function of aquatic plant assemblages along a large‐scale altitudinal gradient. We found an altitudinal decline in the diversity of aquatic plants and different patterns in the phylogenetic and functional structures of aquatic plant assemblages. These findings indicate that functional traits have high phenotypic plasticity and are more affected by environments than phylogenetic relationships which are mainly shaped by evolutionary processes.
The rhodium‐catalyzed amidation of substituted benzoic acids with isocyanates by directed CH functionalization followed by decarboxylation to afford the corresponding N‐aryl benzamides is ...demonstrated, in which the carboxylate serves as a unique, removable directing group. Notably, less common meta‐substituted N‐aryl benzamides are generated readily from more accessible para‐ or ortho‐substituted groups by employing this strategy.
Kill the director: The rhodium‐catalyzed amidation of substituted benzoic acids with isocyanates via directed CH functionalization followed by decarboxylation to afford the corresponding N‐aryl benzamides is demonstrated. The carboxylate serves as a unique, removable directing group. Notably, less common meta‐substituted N‐aryl benzamides are formed readily from more accessible para‐ or ortho‐substituted groups by employing this strategy.
Random composites of iron particles hosted in porous alumina were prepared from a facile impregnation‐reduction process. Interestingly, when the iron content exceeds the percolation threshold, the ...interconnection of iron particles results in the formation of iron networks. The composites then change from capacitive to inductive and the conductive mechanism changes from hopping conduction to metal‐like conduction. The negative permittivity was attributed to the plasma oscillation of delocalized electrons in iron networks, while the negative permeability could be ascribed to the strong diamagnetic response of current loops in iron networks. The negative permittivity behavior of the iron/alumina composite was analyzed using Drude model. Additionally, the fitting results indicated that the effective plasma frequency of the iron/alumina composite is much lower than bulk iron. Further investigations show that, the iron content and reduction temperature can easily tune the amplitude and frequency ranges of the negative permittivity and permeability. Moreover, the negative permittivity region and the negative permeability region can be pushed to the same frequency region by adjusting the iron content and reduction temperature. The impregnation‐reduction process opens a new way for the realization of tunable negative permittivity and permeability in random composites, and has great potential for the preparation of new types of double negative materials.
Iron particles are hosted in porous alumina via a facile impregnation‐reduction process. When the iron content exceeds the percolation threshold, iron networks are formed. The iron content and reduction temperature can easily tune the amplitude and frequency range of the negative permittivity and permeability. The impregnation‐reduction process has great potential for the preparation of random composites with tunable double negative properties.
Accurately identifying the key links in active distribution network (ADN) that affect the system's safety and stability is of great significance to improve the efficiency of operation and maintenance ...and risk early warning for distribution network (DN). In this study, the node resilience (NR) is first proposed as an indicator for structural stability identification of DN. Then, a critical node identification method considering the security, economy and structure stability in ADN is proposed, which uses the NR, the utility risks of branch load change, node voltage deviation and line loss variation as the identification indicators. Also, combining with subjective experience and objective data, the comprehensive evaluation method of critical nodes is improved, and the multilevel and multidimensional evaluation model of critical nodes is constructed. Furthermore, the time sequence of load change and photovoltaic output is considered. Finally, the rationality and effectiveness of the proposed method are proved by taking IEEE 33-bus system and an actual ADN as examples.
Premise
Determining how xylem vessel diameters vary among plants and across environments gives insights into different water‐use strategies among species and ultimately their distributions. Here, we ...tested the vessel dimorphism hypothesis that the simultaneous occurrence of many narrow and a few wide vessels gives lianas an advantage over trees in seasonally dry environments.
Methods
We measured the diameters of 13,958 vessels from 15 liana species and 10,430 vessels from 16 tree species in a tropical seasonal rainforest, savanna, and subtropical evergreen broadleaved forest. We compared differences in mean and hydraulically weighted vessel diameter (MVD and Dh), vessel density (VD), theoretical hydraulic conductivity (Kt), vessel area fraction (VAF), and wood density (WD) between lianas and trees and among three sites.
Results
Nine liana species and four tree species had dimorphic vessels. From the tropical seasonal rainforest to the savanna, liana MVD, Dh and Kt decreased, and VD and WD increased, while only tree WD increased. From the tropical seasonal rainforest to the subtropical forest, six wood traits remained unchanged for lianas, while tree MVD, Dh and Kt decreased and VD increased. Trait space for lianas and trees were more similar in the savanna and more divergent in the subtropical forest compared to the tropical seasonal rainforest.
Conclusions
These results suggest that lianas tend to possess greater vessel dimorphism, which may explain how lianas grow well during seasonal drought, influencing their unique distribution across tropical rainfall gradients.
This paper investigates the coordinated voltage control problem for smart distribution grid with the integration of distributed generation (DG). By actively participating in voltage control together ...with under-load tap changer and shunt capacitors, DG can operate more effectively in the distribution network. The objective of the proposed control method is to minimize the active power loss in the distribution system and to decrease the number of switching device operations while maintaining the grid voltage within the allowable range. Nondispatchable and dispatchable DG are both considered in the control method. To solve the mixed integer nonlinear programming problem, the trust region sequential quadratic programming method is integrated with the branch and bound approach to iteratively approximate the optimization with trust region guidance. Numerical tests on a standard 10-kV distribution system, a real 10-kV distribution system in the Sichuan province of China, and the IEEE 13-bus demonstrate the applicability of the proposed coordinated voltage control method.
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