Search

In multi-objective optimization, the Pareto-optimal solutions must be widely and uniformly distributed on the Pareto-optimal front. When this condition is satisfied, decision makers can choose satisfactory solutions. In this paper, gaps in the evolving nondominated front are filled by a multi-objective evolutionary algorithm using a uniformly evolving scheme (MOEA/UE), thus generating a uniform and wide Pareto-optimal front. The MOEA/UE first calculates the distance between the points on the nondominated front and identifies those with relatively wide gaps. At the widely spaced points, the objective and constraint functions are approximated by linear functions expressed as Taylor series in auxiliary linear programs. Finally, the MOEA/UE solves these auxiliary linear programs and retains the optimal or intermediate solutions as the potentially superior individuals that will be selected in the next generation of the population. Convergence toward potentially superior solutions is accelerated by a mutation operator (a basic differential evolution operator). In constrained multi-objective optimization problems, the MOEA/UE implements a new constraint-handling strategy that pulls infeasible solutions into or nearby the feasible domain. Experimental results illustrate that MOEA/UE obtains wider and more uniform Pareto-optimal fronts and better Pareto-optimal solutions. [ABSTRACT FROM AUTHOR]

Interval programming is one of main approaches treating imprecise and uncertain elements involved in optimization problems. In this paper, an interval linear fractional bilevel program is considered, which is characterized in that both objective coefficients and the right-hand side vector are interval numbers, and an evolutionary algorithm (EA) is proposed to solve the problem. First, the interval parameter space of the follower's problem is taken as the search space of the proposed EA. For each individual, one can evaluate it by dealing with a simplified interval bilevel program in which only the leader's objective involves interval parameters. In addition, the optimality conditions of linear fractional programs are applied to convert and solve the simplified problem. Finally, some computational examples were solved and the results show that the proposed algorithm is efficient and robust. [ABSTRACT FROM AUTHOR]

Laser powder bed fusion (LPBF) additive manufacturing, as a novel technique provides broad benefits in thermoelectric materials synthesis, such as enhanced printing speed, reduced waste materials, and customized dimension design. The high energy density of laser could potentially balance the synthesis rate and thermoelectric figure-of-merit zT , but the correlations between laser energy and material performance are still vague. Herein, Bi 0.5 Sb 1.5 Te 3 bulks are directly synthesized by LPBF with a recorded synthesis rate of 254 g h−1. The maximum zT , without any post-processing, reaches 1.1 at 75 °C. Induced nanoscale pores by high laser energy printing, obtain a comparable diameter to phonon mean free path, leading to reduced lattice thermal conductivity and enhanced TE performance. We found that input laser energy critically affected thermoelectric performance and concluded the correlation between volumetric energy density E V and power factor PF , PF = 9.05 E V 2 – 30.01 E V + 48.84. It potentially predicts thermoelectric performance with inputted laser energy density. [ABSTRACT FROM AUTHOR]

Network coding can encode and forward the received data packets to save the network resources and improve the bandwidth utilization in cloud computing environment. To resist the pollution attacks and improve the computational efficiency in network coding, we construct certificateless multi-source elliptic curve ring signcryption (CL-MSECRSC) scheme suitable for cloud computing, its security relies on the hardness of elliptic curve discrete logarithm (ECDL) and elliptic curve computation Diffie-Hellman (ECCDH) problems. CL-MSECRSC has the properties of anti-forgery, anti-pollution, confidentiality and unconditional anonymity; also, scalar multiplication operations greatly save its computation overhead. [ABSTRACT FROM AUTHOR]

• In this paper, we construct the first certificateless ring signcryption for multi-source network coding (MSNC CLRSC) , which is a secure and efficient scheme. In MSNC CLRSC, the private key is used to sign the message vector; and the signed message vector is transmitted to the receiving nodes that can combine and verify the signcrypted ciphertext without the private key of actual signcrypter; furtherly, the receiving nodes filter out the polluted information. MSNC CLRSC has broad application prospects in 5G wireless network, UAV wireless communication network, wireless ad hoc network and wireless sensor network. Network coding can make the intermediate nodes encode the messages, and it has the merits of large network throughput, high resource utilization rate and strong system robustness. Traditional certificateless ring signcryption cannot be used in the network coding environment, so we construct one certificateless ring signcryption for multi-source network coding (MSNC CLRSC), in which actual signcrypter can anonymously signcrypt a message on behalf of a group of users including himself. MSNC CLRSC is provably confidential and unforgeable under the hardness of the co-decisional bilinear Diffie-Hellman and co-computational Diffie-Hellman problems in the random oracle model; moreover, it can resist the pollution attacks and has relatively low computation complexity. [ABSTRACT FROM AUTHOR]