Multi-Objective Optimization of Multi-Product Parallel Disassembly Line Balancing Problem Considering Multi-Skilled Workers Using a Discrete Chemical Reaction Optimization Algorithm

This work investigates a multi-product parallel disassembly line balancing problem considering multi-skilled workers.A mathematical model for the parallel disassembly line is established to achieve maximized disassembly profit and minimized workstation cycle time.Based on a product’s AND/OR graph,matrices for task-skill,worker-skill,precedence relationships,and disassembly correlations are developed.A multi-objective discrete chemical reaction optimization algorithm is designed.To enhance solution diversity,improvements are made to four reactions:decomposition,synthesis,intermolecular ineffective collision,and wall invalid collision reaction,completing the evolution of molecular individuals.The established model and improved algorithm are applied to ball pen,flashlight,washing machine,and radio combinations,respectively.Introducing a Collaborative Resource Allocation(CRA)strategy based on a Decomposition-Based Multi-Objective Evolutionary Algorithm,the experimental results are compared with four classical algorithms:MOEA/D,MOEAD-CRA,Non-dominated Sorting Genetic Algorithm Ⅱ(NSGA-Ⅱ),and Non-dominated Sorting Genetic Algorithm Ⅲ(NSGA-Ⅲ).This validates the feasibility and superiority of the proposed algorithm in parallel disassembly production lines.

Solution to the Balanced Academic Curriculum Problem Using Tabu Search

The Balanced Academic Curriculum Problem （BACP） is a constraint satisfaction problem classified as （Non-deterministic Polynomial-time Hard） NP-Hard. This problem consists in the allocation of courses in the periods that are part of a curriculum such that the prerequisites are satisfied and the load of courses is balanced for the students. This paper presents the solution for a modified BACP where the academic loads and number of curses may be the same or different for each one of the periods and allows having some courses in a specific period. This problem is modeled as an integer programming problem and is proposed the use of Tabu search with short-term memory for its solution because it is not possible to find solutions for all the instances of this modified problem with an exact method.

On the upper bounds of (1,0)-super solutions for the regular balanced random (k,2s)-SAT problem

This paper explores the conditions which make a regular balancedrandom(k,2s)-CNFformula(1,O)-unsatisfiable with high probability.The conditions also make a random instance of the regular balanced(k-1,2(k-1)s)-SAT problem unsatisfiable with high probability,where the instance obeys a distribution which differs from the distribution obeyed by a regular balanced random(k-1,2(k-1)s)-CNF formula.Let F be a regular balanced random(k,2s)-CNF formula where k≥3,then there exists a number so such that F is(1,O)-unsatisfiable with high probability if s>so.A numerical solution of the number so when k e(5,6,...,14)is given to conduct simulated experiments.The simulated experiments verify the theoretical result.Besides,the experiments also suggest that F is(1,O)-satisfiable with high probability if s is less than a certain value.

RIGOROUS ESTIMATES ON BALANCE LAWS IN BOUNDED DOMAINS

The initial-boundary value problem for a general balance law in a bounded domain is proved to be well posed. Indeed, we show the existence of an entropy solution, its uniqueness and its Lipschitz continuity as a function of time, of the initial datum and of the boundary datum. The proof follows the general lines in [4], striving to provide a rigorous treatment and detailed references.

Stabilized Crouzeix-Raviart element for the coupled Stokes and Darcy problem

This paper introduces a new stabilized finite element method for the coupled Stokes and Darcy problem based on the nonconforming Crouzeix-Raviart element. Optimal error estimates for the fluid velocity and pressure are derived. A numerical example is presented to verify the theoretical predictions.

Perspectives for the recovery of rare earths from end-of-life fluorescent lamps

This vision paper discusses the advantages and disadvantages of the three main options for the recycling of rare-earth ele- ments from end-of-life fluorescent lamps： （1） direct re-use of the lamp phosphor mixture; （2） separation of the lamp phosphor mixture into the different phosphor components; （3） recovery of the rare-earth content. An overview is given of commercial activities in Europe in the domain of recycling of materials from end-of-life fluorescent lamps and the recovery of rare earths from these lamps. The collection of end-of-life fluorescent lamps is currently driven by a legal framework that prohibited the release of mercury to the environment. The contaminations of the lamp phosphor powders by mercury and by small glass particles of crushed fluorescent lamps are limiting factors in the recycling process. Research should be directed to an advanced clean-up of the reclaimed lamp phosphor fraction, and in particular to the removal of mercury and glass fragments. The recovery of rare earths from the lamp phosphors could be facilitated by taking advantage of the differences in resistance of the different lamp phosphors by chemical attack by inorganic ac- ids and bases.