A tabu search approach for mixed-model parallel assembly line balancing problem (type II)

There are two types of assembly line balancing problems (ALBPs), which have received a great attention in the literature during the past four decades: types I and II. Both versions of ALBP are NP-hard and cannot be solved by exact methods. This paper presents an efficient tabu search (TS) metaheuristic approach for allocating tasks to balance the mixed-model production through the parallel assembly lines. Firstly, an initial solution is determined by a heuristic algorithm. Secondly, an optimum cycle time for each line in the mixed-model parallel assembly line (MMPAL) is calculated through the TS. The developed methodology, tabu search mixed-model parallel assembly line balancing (TMMPALB) model, is tested on test problems producing three and four products. Computational experiments show that the TMMPALB produces good enough solutions in case of MMPALs. The results of the proposed procedure improve cycle times of 77 test problems out of 87

A hybrid algorithm to solve the flexible oil refinery production planning problem

The goal of production planning in a refinery is to produce as many valuable products as possible such as gasoline, jet fuel, diesel, etc., while meeting market demand and other constraints. Crude oil refining is one of the most complex chemical industries; Therefore, optimizing the production planning of an oil refinery is considered as one of the most difficult and challenging issues in this field. Due to rapid changes in industry-related technologies such as the construction of new catalysts, the design of more flexible process units, the flexibility of refineries is increasing rapidly. With the flexibility of refineries, their production planning requires a mathematical model that can be used to make the best decision at the right time to meet market demand at the lowest production cost. In this paper, the production planning of a flexible refinery is modeled using mathematical relationships between macro parameters such as product demand, production conditions, fixed and variable production costs, and inventory costs of petroleum products. To solve it, a hybrid algorithm of combining genetic algorithm and fix and optimize is proposed. The results with using of 63 simulated problems in small, medium and large dimensions show that the near-optimal solution obtained from the hybrid method deviates 0.23 and 0.12 percent of the exact solution of the problem on average in small and medium dimensions respectively. Also in large dimensions where it was not possible to calculate the exact answer by the computer, this algorithm can answer in an average of 87 seconds

A distribution planning model for natural gas supply chain: A case study

In this paper, a real-world case study of a natural gas supply chain is investigated. By using concepts related to natural gas industry and the relations among the components of transmission and distribution network, a six-level supply chain has been introduced and presented schematically. The defined supply chain is a single-objective, multi-period, and single-product problem that is formulated as a mixed integer non-linear programming model, which can easily be linearized. The objective of this model is to minimize direct or indirect distribution costs. There are six groups of constraints including capacity, input and output balancing, demand satisfaction, network flow continuity, and relative constraints to the required binary variables. The solution algorithm of the problem is hierarchical; in each step, one section of the problem is solved using an exact method; the outputs of this section are passed to the next relative section as inputs. Finally, it is shown that the problem has been solved in a reasonable time and desirable results are attained. The use of proposed model and its solution approach have been studied in two gas trunk lines, to present the priority of its cost saving.Distribution planning Natural gas Supply chain

Customer knowledge management application in Malaysian mobile service providers

In this paper, the aim was to examine the essentially of Customer Knowledge Management (CKM) in Malaysia mobile service providers. In addition, how would customers accept CKM would be discussed. The survey respondents were limited to college students from three main university of Malaysia. It is found in the survey that the current system would not fully satisfy clients, and they need a more enhanced knowledge sharing system. Furthermore, respondents showed their potential and ability to share knowledge through CKM desired channels with mobile service providers to get better and enlarged services

Improvement of tops spinning manufacturing with CNC lathe

This paper presents an increasing demand of Top-Spinning (T-S) has resulted in the production of high quantity of TS. Currently, the production of T-S is very low and not up to the required demand. This is due to the old machine used as well as an old method in the manufacturing of T-S, which lead to the longer time taken compared to the new technology found in this project. The cardinal purpose of this project is to identify the machining sequence with the selection of a suitable tool and reducing machining cycle time with the use of CNC Lathe for manufacturing T-S. In ensuring a successful and optimum result of the project, manufacturing T-S with CNC Lathe will be assisted by Mathematisch Technishe software Entwicklung (MTS) and Master CAM simulation to determine machining sequence, cutting tools, technology parameters and machining cycle time. The data extracted from MTS, and CAD/CAM simulation process will then be used for manufacturing T-S on CNC Lathe technology. This project emphasizes on the importance of determining machining sequence, cutting tools to manufacture T-S in any shape available and also resolving machining cycle time. The result from MTS and CAD/CAM with three analyses of machining sequence, cutting tool and technology parameters will be used to proceed on CNC Lathe. Finally, with the utilization of the data extracted from MTS software, and CAD/CAM simulation has successfully impacted the reduction on overall machining cycle time while producing T-S