Enhancing Harmony Search Parameters Based On Step And Linear Function For Bus Driver Scheduling And Rostering Problems

Optimization is a major challenge in numerous practical world problems.According to the “No Free Lunch (NFL)” theorem,there is no existing single optimizer algorithm that is able to resolve all issues in an effective and efficient manner.It is varied and need to be solved according to the specific capabilities inherent to certain algorithms making it hard to foresee the algorithm that is best suited for each problem.As a result,the heuristic technique is adopted for this research as it has been identified as a potentially suitable algorithm.Alternative heuristic algorithms are also suggested to obtain optimal solutions with reasonable computational effort.However,the heuristic approach failed to produce a solution that nears optimum when the complexity of a problem increases;therefore a type of nature-inspired algorithm known as meta-euristics which utilises an intelligent searching mechanism over a population is considered and consequently used.The meta-heuristic approach is widely used to substitute heuristic terms and is broadly applied to address problems with regards to driver scheduling.However,this meta-heuristic technique is still unable to address the fairness issue in the scheduling and rostering problems.Hence,this research proposes a strategy to adopt an amendment of the harmony search algorithm in order to address the fairness issue which in turn will escalate the level of fairness in driver scheduling and rostering.The harmony search algorithm is classified as a meta-heuristics algorithm that is capable of solving hard and combinatorial or discrete optimisation problems.In this respect,the three main operators in harmony search,namely the Harmony Memory Consideration Rate (HMCR),Pitch Adjustment Rate (PAR) and Bandwidth (BW) play a vital role in balancing local exploitation and global exploration.These parameters influence the overall performance of the HS algorithm,and therefore it is crucial to fine-tune them. Therefore,it is of great interest that we find adjustments for these parameters in this research.There are two contributions to this research.The first one is having HMCR parameter using step function and the linear increase function while the second is applying the fret spacing concept on guitars that is associated with mathematical formulae is also applied in the BW parameter.There are three proposed models on the alteration of HMCR parameters based on the use of the fundamental step function;namely,the constant interval of step function, and its dynamic increase and decrease interval functions.The experimental results revealed that our proposed approach is superior to other state of the art harmony searches either in specific or generic cases. This is achieved by using a first type of association between the linear increase function with a second model of the dynamic increase of step function being remarkable in other combinations and also other models.In conclusion,this proposed approach managed to generate a fairer roster and was thus capable of maximising the balancing distribution of shifts and routes among drivers,which contributed to the lowering of illness, incidents,absenteeism and accidents

THE SEVEN CASES UNSTRUCTURED TRIANGULATION TECHNIQUE FOR RADIATIVE HEAT TRANSFER APPROXIMATION IN AN ETHYLENE FURNACE CRACKER

Radiative heat distribution inside an ethylene cracker furnace is often modelled using the finite volume and finite element methods. In both cases, meshes in the form of rectangles and triangles are needed to serve as the approximating points in the domain. In this paper, a new method called the Seven Cases Unstructured Triangulation Technique (7CUTT) is proposed for meshing the domain inside the cracker furnace, integrated with the deployment of sensors on the wall to obtain the boundary value. 7CUTT is an enhanced version of the Standard Advancing Front Technique (SAFT) which two normal cases in SAFT are extended to the total of seven cases for consideration during the element creation procedure for initial mesh generation. The focus of this method is to construct the initial triangular meshes with the requirement of (1) having the location of sensors deployed along the wall as boundary nodes as well as forming boundary elements, (2) generating nodes at a certain boundary with linearly different lengths of boundary edges as interior gradation controls and (3) constructing the triangular element directly in every iteration without having to re-order the Front or delete the existing elements. There are three contributions from this paper, the first one is the introduction of seven extended cases for consideration for the element creation procedure, the second is the layer concept to generate edges with linearly different lengths and the third is the post-processing mesh procedure to improve the quality of the mesh that is suitable for 7CUTT. The final mesh is obtained once the post-processing procedure of improving the mesh quality is applied to the initial mesh. 7CUTT provides the framework for the heat to be approximated using the discrete ordinate method, which is a variant of the finite volume method. Simulation results produced using FLUENT support the findings for effectively approximating the flue gas temperature distribution, the circumferential radiative heat flux incident at the reactor coils as well as the circumferential reactor coil temperature in the furnace at the end of the study