113 research outputs found
OPTIMAL POWER FLOW WITH TCSC DEVICE USING CUCKOO OPTIMIZATION ALGORITHM
Optimal Power Flow (OPF) problem is an optimization tool through which secure and economic operating conditions of power system is obtained. In recent years, Flexible AC Transmission System (FACTS) devices, have led to the development of controllers that provide controllability and flexibility for power transmission. Series FACTS devices such as Thyristor controlled series compensators (TCSC), with its ability to directly control the power flow can be very effective to power system security. Thus, integration TCSC in the OPF is one of important current problems and is a suitable method for better utilization of the existing system. This paper is applied Cuckoo Optimization Algorithm (COA) for the solution of the OPF problem of power system equipped with TCSC. The proposed approach has been examined and tested on the IEEE 30-bus system. The results presented in this paper demonstrate the potential of COA algorithm and show its effectiveness for solving the OPF problem with TCSC devices over the other evolutionary optimization techniques
Optimal placement of battery energy storage system considering penetration of distributed generations
This paper proposes the optimal problem of location and power of the battery-energy-storage-system (BESS) on the distribution system (DS) considering different penetration levels of distributed generations (DGs). The objective is to minimize electricity cost of the DS in a typical day considering the power limit of DG fed to the DS. Growth optimizer (GO) is first applied to search the BESS’s location and power for each interval of the day. The considered problem and GO method are evaluated on the 18-node DS with two penetrations levels of photovoltaic system and wind turbine. The results demonstrate that the optimal BESS placement significantly reduces electricity cost. Furthermore, the optimal BESS location and power also help to reduce the cut capacity of DGs as their power greater than the load demand. The compared results between GO and particle swarm optimization (PSO) method have shown that GO reaches the better performance than PSO in term the optimal solution and the statistical results. Thus, GO is an effective approach for the BESS placement problem
Modified sunflower optimization for network reconfiguration and distributed generation placement
This paper proposed modified sunflower optimization (MSFO) for the combination of network reconfiguration and distributed generation placement problem (NR-DGP) to minimize power loss of the electric distribution system (EDS). Sunflower optimization (SFO) is inspired form the ideal of sunflower plant motion to get the sunlight and its reproduction. To enhance the performance of SFO, it is modified to MSFO wherein, the pollination and mortality techniques have been modified by using Levy distribution and mutation of the best solutions. The results are evaluated on two test systems. The efficiency of MSFO is compared with that of the original SFO and other algorithms in literature. The comparisons show that MSFO outperforms to SFO and other methods in obtained optimal solution. Furthermore, MSFO demonstrates the better statistical results than SFO. So, MSFO can be a powerful approach for the NR-DGP problem
Optimal solutions for fixed head short-term hydrothermal system scheduling problem
In this paper, optimal short-term hydrothermal operation (STHTO) problem is determined by a proposed high-performance particle swarm optimization (HPPSO). Control variables of the problem are regarded as an optimal solution including reservoir volumes of hydropower plants (HdPs) and power generation of thermal power plants (ThPs) with respect to scheduled time periods. This problem focuses on reduction of electric power generation cost (EPGC) of ThPs and exact satisfactory of all constraints of HdPs, ThPs and power system. The proposed method is compared to earlier methods and other implemented methods such as particle swarm optimization (PSO), constriction factor (CF) and inertia weight factor (IWF)-based PSO (FCIW-PSO), two time-varying acceleration coefficient (TTVACs)-based PSO (TVAC-PSO), salp swarm algorithm (SSA), and Harris hawk algorithm (HHA). By comparing EPGC from 100 trial runs, speed of search and simulation time, the suggested HPPSO method sees it is more robust than other ones. Thus, HPPSO is recommended for applying to the considered and other problems in power systems
Determining optimal location and size of capacitors in radial distribution networks using moth swarm algorithm
In this study, the problem of optimal capacitor location and size determination (OCLSD) in radial distribution networks for reducing losses is unraveled by moth swarm algorithm (MSA). MSA is one of the most powerful meta-heuristic algorithm that is taken from the inspiration of the food source finding behavior of moths. Four study cases of installing different numbers of capacitors in the 15-bus radial distribution test system including two, three, four and five capacitors areemployed to run the applied MSA for an investigation of behavior and assessment of performances. Power loss and the improvement of voltage profile obtained by MSA are compared with those fromother methods. As a result, it can be concluded that MSA can give a good truthful and effective solution method for OCLSD problem
Improved particle swarm optimization algorithms for economic load dispatch considering electric market
Economic load dispatch problem under the competitive electric market (ELDCEM) is becoming a hot problem that receives a big interest from researchers. A lot of measures are proposed to deal with the problem. In this paper, three versions of PSO method such as conventional particle swarm optimization (PSO), PSO with inertia weight (IWPSO) and PSO with constriction factor (CFPSO) are applied for handling ELDCEM problem. The core duty of the PSO methods is to determine the most optimal power output of generators to obtain total profit as much as possible for generation companies without violation of constraints. These methods are tested on three and ten-unit systems considering payment model for power delivered and different constraints. Results obtained from the PSO methods are compared with each other to evaluate the effectiveness and robustness. As results, IWPSO method is superior to other methods. Besides, comparing the PSO methods with other reported methods also gives a conclusion that IWPSO method is a very strong tool for solving ELDCEM problem because it can obtain the highest profit, fast converge speed and simulation time
Revisiting LARS for Large Batch Training Generalization of Neural Networks
LARS and LAMB have emerged as prominent techniques in Large Batch Learning
(LBL), ensuring the stability of AI training. One of the primary challenges in
LBL is convergence stability, where the AI agent usually gets trapped into the
sharp minimizer. Addressing this challenge, a relatively recent technique,
known as warm-up, has been employed. However, warm-up lacks a strong
theoretical foundation, leaving the door open for further exploration of more
efficacious algorithms. In light of this situation, we conduct empirical
experiments to analyze the behaviors of the two most popular optimizers in the
LARS family: LARS and LAMB, with and without a warm-up strategy. Our analyses
give us a comprehension of the novel LARS, LAMB, and the necessity of a warm-up
technique in LBL. Building upon these insights, we propose a novel algorithm
called Time Varying LARS (TVLARS), which facilitates robust training in the
initial phase without the need for warm-up. Experimental evaluation
demonstrates that TVLARS achieves competitive results with LARS and LAMB when
warm-up is utilized while surpassing their performance without the warm-up
technique
Biocompatible chitosan-functionalized upconverting nanocomposites
Simultaneous integration of photon emission and biocompatibility into nanoparticles is an interesting strategy to develop applications of advanced optical materials. In this work, we present the synthesis of biocompatible optical nanocomposites from the combination of near-infrared luminescent lanthanide nanoparticles and water-soluble chitosan. NaYF4:Yb,Er upconverting nanocrystal guests and water-soluble chitosan hosts are prepared and integrated together into biofunctional optical composites. The control of aqueous dissolution, gelation, assembly, and drying of NaYF4:Yb,Er nanocolloids and chitosan liquids allowed us to design novel optical structures of spongelike aerogels and beadlike microspheres. Well-defined shape and near-infrared response lead upconverting nanocrystals to serve as photon converters to couple with plasmonic gold (Au) nanoparticles. Biocompatible chitosan-stabilized Au/NaYF4:Yb,Er nanocomposites are prepared to show their potential use in biomedicine as we find them exhibiting a half-maximal effective concentration (EC50) of 0.58 mg mL–1 for chitosan-stabilized Au/NaYF4:Yb,Er nanorods versus 0.24 mg mL–1 for chitosan-stabilized NaYF4:Yb,Er after 24 h. As a result of their low cytotoxicity and upconverting response, these novel materials hold promise to be interesting for biomedicine, analytical sensing, and other applications
Label driven Knowledge Distillation for Federated Learning with non-IID Data
In real-world applications, Federated Learning (FL) meets two challenges: (1)
scalability, especially when applied to massive IoT networks; and (2) how to be
robust against an environment with heterogeneous data. Realizing the first
problem, we aim to design a novel FL framework named Full-stack FL (F2L). More
specifically, F2L utilizes a hierarchical network architecture, making
extending the FL network accessible without reconstructing the whole network
system. Moreover, leveraging the advantages of hierarchical network design, we
propose a new label-driven knowledge distillation (LKD) technique at the global
server to address the second problem. As opposed to current knowledge
distillation techniques, LKD is capable of training a student model, which
consists of good knowledge from all teachers' models. Therefore, our proposed
algorithm can effectively extract the knowledge of the regions' data
distribution (i.e., the regional aggregated models) to reduce the divergence
between clients' models when operating under the FL system with non-independent
identically distributed data. Extensive experiment results reveal that: (i) our
F2L method can significantly improve the overall FL efficiency in all global
distillations, and (ii) F2L rapidly achieves convergence as global distillation
stages occur instead of increasing on each communication cycle.Comment: 28 pages, 5 figures, 10 table
The 3-3-1 Model with Arbitrarily Charged Leptons
The gauge  model based on  group with arbitrarily electric charged exotic leptons is presented. The mass eigenvalues and eigenstates for  neutral gauge bosons are presented in the general form. We show that in the 3-3-1 models, there always exists triple Higgs self-coupling. The lepton number operator is also presented
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