Optimal Scheduling of Casting Sequence Using Genetic Algorithms

Scheduling a casting sequence involving a number of orders with different casting weights and satisfying due dates of is an important optimization problem often encountered in foundries. In this article, we attempt to solve this complex, multi-variable, and multi-constraint optimization problem by using different implementations of genetic algorithms (GAs). In comparison with a mixed-integer linear programming solver, GAs with problem-specific operators are found to provide faster (with a subquadratic computational time complexity) and more reliable solutions to very large (more than 1 million integer variables) casting sequence optimization problems. In addition to solving the particular problem, the study demonstrates how problem-specific information can be introduced in a GA for solving complex real-world problems.     

Effect of Gd3+ substitution on physicochemical properties of superparamagnetic Fe3O4 nanoparticles

Journal of Materials Science: Materials in Electronics - The present study depicts physicochemical characteristics of Gd3+ modified Fe3O4 nanoparticles synthesized via the sol-gel combustion...     

Study on Dynamic Participation of Wind Turbines in Automatic Generation Control of Power Systems

This article presents the design of optimal automatic generation control regulators for an interconnected power system incorporating dynamic participation of doubly fed induction generator based wind turbines. Two power system models are identified for the investigations. Power system model 1 is a two-area interconnected power system consisting of identical plants with non-reheat turbines, whereas power system model 2 consists of identical plants with non-reheat turbines and dynamic participation of doubly fed induction generator based wind turbines in both areas. An AC tie-line is used as area interconnection in both power system models. The designed optimal automatic generation control regulators are implemented, and the system dynamic responses for various system states are obtained considering a 1% load disturbance in one of the areas. The pattern of closed-loop eigenvalues is also determined to investigate system stability. From the investigations carried out in the work, it is inferred that the incorporation of doubly fed induction generator based wind turbines in both areas has appreciably improved the dynamic performance of the system under consideration. Moreover, system stability is ensured for both power system models.     

Leaf Image-Based Plant Disease Identification Using Color and Texture Features

Wireless Personal Communications - Identification of plant disease is usually done through visual inspection or during laboratory examination which causes delays resulting in yield loss by the time...     

Through-Thickness Deformation Gradient in a Part-Pilgered Zirconium Tube: Experimental Measurements and Numerical Validation

Metallurgical and Materials Transactions A - Through-thickness microstructure development and residual stress evolution were explored in a part-pilgered Zircaloy-4 tube. Clear gradients in...     

黄原酸盐促进剂在异丁烯基弹性体硫化中的应用

异丁烯基弹性体包括 IIR、卤化丁基橡胶(HIIR)及其星形支化产品.IIR 和 HIlR(BIIR 和 CIIR)硫化与通用橡胶不同.IIR 分子主链的不饱和度约为 2%.HIIR 在丁基主链上引入溴或氯,提高了聚合物主链上异戊二烯单元的反应活性.     

Optimal allocation of testing resources for statistical simulations

Statistical estimates from simulation involve uncertainty caused by the variability in the input random variables due to limited data. Allocating resources to obtain more experimental data of the input variables to better characterize their probability distributions can reduce the variance of statistical estimates. The methodology proposed determines the optimal number of additional experiments required to minimize the variance of the output moments given single or multiple constraints. The method uses multivariate t-distribution and Wishart distribution to generate realizations of the population mean and covariance of the input variables, respectively, given an amount of available data. This method handles independent and correlated random variables. A particle swarm method is used for the optimization. The optimal number of additional experiments per variable depends on the number and variance of the initial data, the influence of the variable in the output function and the cost of each additional experiment. The methodology is demonstrated using a fretting fatigue example.     

Blockchain-inspired lightweight trust-based system in vehicular networks

A decentralized application runs on the blockchain network without the intervention of a central authority. Transparency in transactions and security in vehicular networks are the issues for central systems. The proposed system uses blockchain-based smart contracts, which eliminate the requirement for any third-party verification. Additionally, with signature verification and reduced overhead, smart contracts also help in a fast and secure transaction. This study suggests a trust-based system paradigm where certificate authority (CA) is employed for vehicle registration. We also propose a blockchain-based system that provides efficient two-way authentication and key agreement through encryption and digital signatures. The analysis of the proposed model reveals that it is an efficient way of establishing distributed trust management, which helps in preserving vehicle privacy. The proposed scheme is tested in Automated Validation of Internet Security-sensitive Protocols (AVISPA), and security parameters verification in Network Simulator 2(NS2) also shows that the proposed scheme is more effective in comparison with existing schemes in terms of authentication cost, storage cost, and overhead.     

Performance enhancement of a hydro-hydro power system using RFB and TCPS

The design of load frequency control (LFC) for the hydro-hydro power system suffers from poor dynamic performance owing to large time constants associated with hydro power generations. The dynamic performance of the hydro-hydro power system can be improved using a thyristor control phase shifter (TCPS) and energy storage battery system. This paper presents a comprehensive study on LFC of an interconnected hydro-hydro power system having TCPS in series with the tie-line and redox flow battery (RBF) at the terminal of one area through few and available state technique, i.e. the output feedback technique. The LFC are designed with the help of few and available states and the performance is judged for typical demand change in the power system area and the results are matched with the LFC obtained via a technique that require all system states, i.e. full state feedback in order to justify the effectiveness of the designed LFC in terms of achieved feedback gains, eigenvalues and the dynamic system responses.

Abbreviations: AC: Alternating Current; BESS: Battery Energy Storage System; FACTS: Flexible Alternating Current Transmission System; LFC: Load Frequency Control; RFB: Redox Flow Battery; SSSC: Static Synchronous Series Compensator; SMES: Superconducting Magnetic Energy Storage; TCPS: Thyristor Control Phase Shifter; UPFC: Unified Power Flow Control