Smart Computing and Systems Engineering (SCSE)
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Item Simulation-Based Efficiency Assessment of Integrated First-Mile Pickup and Last-Mile Delivery in an E-Commerce Logistics Network(Department of Industrial Management, Faculty of Science, University of Kelaniya Sri Lanka, 2022) Ranathunga, M. I. D.; Wijayanayake, A. N.; Niwunhella, D. H. H.Logistics operations are crucial in the e-commerce supply chain as they deal with high costs as well as they have a significant environmental impact. The first-mile and last-mile delivery operations in e-commerce logistics are regarded as the operations with the highest costs. As a result, e-commerce service providers are keen to improve their first mile and last-mile delivery processes. Therefore, this study has been conducted to optimize transportation cost and distance of combined first-mile pickup and last-mile delivery operations while meeting some practical requirements such as a variety of package types, package compatibility on different types of vehicles, and a heterogeneous fleet of vehicles. After a careful literature review, this paper introduces a mathematical model to optimize the simultaneous first-mile pickup and last-mile delivery. The proposed mathematical model was simulated in SupplyChainGuru® modelling and simulation software. The study concluded that when first-mile pickup and last-mile delivery are routed simultaneously, rather than distributing and collecting the products as two separate operations, the overall cost is minimized by about 34%, and the distance is reduced by about 42% while reducing the number of vehicles on the route and utilising the maximum possible capacity of vehicles. This simultaneous pickup and delivery will improve the routing of the e-commerce logistic supply chain and will serve as a platform for extending the simultaneous pickup and delivery process to other industries as well.Item Analyzing Factors that Impact on Performance of Pickers in Third-Party Logistics Warehouses in Sri Lanka(Department of Industrial Management, Faculty of Science, University of Kelaniya Sri Lanka, 2022) Prasadika, A. P. K. J.; Wijayanayake, A. N.; Niwunhella, D. H. H.Order picking is the most crucial and expensive operation in a warehouse which affects customer satisfaction and the profitability of the warehouse. Picker is the employee who is responsible for the order picking process. So, picker performance is very important in improving the overall performance of the warehouse. Therefore, identifying the factors that have an impact on the performance of the pickers is advantageous. The main objective of this research is to identify the relationship between factors that has an impact on picker and picker performance through the Partial Linear Square – Structural Equation Modelling (PLS-SEM) technique using SmartPLS software. Initially, the most important twelve factors were identified by reviewing the past literature and industry experts’ opinions. They were divided into three main categories based on the characteristics and to reduce the complexity of the model which are picker-related factors, management-related factors, and warehouse-related factors. The data analysis was done in two steps to discover direct and moderator relationships, separately. The product type that the pickers handle is the moderator used in this study. The results of the PLS-SEM analysis show that picker-related factors and warehouse-related factors have a significant impact on picker performance at the significance level of 0.05, while management-related factors have a significant effect on picker performance at the significance level of 0.10. Further, the product type moderates all three relationships. The outcomes of the study help the managers of the warehouses to improve the performance of the pickers so that the overall performance of the warehouse can be improved.Item An Effective Lateral Transhipment Model for A Multi-Location Inventory Setting to Minimize(Department of Industrial Management, Faculty of Science, University of Kelaniya Sri Lanka, 2022) Kumari, A.G.K.C.; Wijayanayake, A. N.; Niwunhella, D. H. H.Managing inventory levels to ensure on-shelf availability of products is a challenge that retailers face on a daily basis. Even though it is desirable to have additional inventory to ensure the availability of products, it increases the inventory holding cost. Hence, retailers use lateral transhipment as a method to redistribute inventory from a location which has excess inventory to another outlet which faces / will face stockouts. This paper proposes a mathematical model to minimize the total cost through proactive lateral transhipment while reducing the stockouts, significantly. A multi-item, multi-location inventory system was considered, and a cost minimization model was developed based on the tradeoff between the potential gain and the transhipment cost. The model was implemented using Python programming language and validated using a real-world data set from one of the leading supermarket chains. The results from the model have shown that it can reduce the total cost and stockout occurrences significantly.Item Solution approaches for combining first-mile pickup and last-mile delivery in an e-commerce logistic network: A systematic literature review(Department of Industrial Management, Faculty of Science, University of Kelaniya Sri Lanka, 2021) Ranathunga, M. I. D.; Wijayanayake, A. N.; Niwunhella, D. H. H.Logistics is one of the primary areas of operation within cutting-edge supply chain operations. In the e-commerce supply chain also logistics operations play a vital part. The logistics operations must be controlled effectively and efficiently since they deal with the high-cost besides environmental impacts. In e-commerce logistics operations, first-mile and last-mile delivery operations are considered as the operations with the highest costs incurred. So, e-commerce service providers are interested in optimizing their first-mile and last-mile delivery operations. Though it is known that the integration of first-mile pickup and last-mile deliveries will minimize the cost of transportation, there are more practical concerns to be taken into account when combining the first-mile pickup and last-mile delivery operations. Capacitated Vehicle Routing Problem (CVRP) is discussed in the literature as a solution approach for this kind of problems. The objective of this study is to provide a comprehensive overview of the current CVRP related literature, including models, algorithmic solution approaches, objectives, and industrial applications, with a focus of identifying interesting study paths for the future to improve distribution in e-commerce logistics networks by combining first-mile pickup and last-mile delivery operations. The findings of the study have demonstrated that constraints and features of Vehicle Routing Problem with Backhauls are very attractive with today's e-commerce operations, and the majority of the cited publications employed approximation methods rather than precise algorithms to solve these types of models.Item A MILP model to optimize the proportion of production quantities considering the ANP composite performance index(Department of Industrial Management, Faculty of Science, University of Kelaniya Sri Lanka, 2021) Thalagahage, N. T. H.; Wijayanayake, A. N.; Niwunhella, D. H. H.The apparel industry is considered as one of the most labor-intensive industries where Production Planning and Control (PPC) is considered as an important function, because of its involvement from scheduling each task in the process to the delivery of customer demand. Line planning is a sub-process within PPC, through which the production orders are allocated to production lines according to their setting and due dates of production completion. The decisions that address line planning functions still heavily rely on the expertise of the production planner. When production planners are required to select production lines for the production of a particular type of product, little emphasis has been placed on ways to apportion certain production orders to the most appropriate production system. In this research, a framework is developed using Analytical Network Process (ANP) which is a Multi-Criteria Decision Making (MCDM) method, enabling the incorporation of all the planning criteria in the selection of a production line. The weighted scores obtained by the best alternative production lines are used in a Linear Programming model to optimize the resource allocation in an apparel firm.Item Model to optimize the quantities of delivery products prioritizing the sustainability performance(Department of Industrial Management, Faculty of Science, University of Kelaniya Sri Lanka, 2021) Prabodhika, A. P. K. J.; Niwunhella, D. H. H.; Wijayanayake, A. N.Many manufacturers and retailers often outsource their logistics functions to Logistics Service Providers (LSPs) to focus more on their core business process. Due to the competitiveness and the popularity of the sustainability concept, those organizations evaluate their prospective LSPs not only based on economic aspects like cost, service quality but also on social and environmental aspects as well when selecting LSPs. This paper proposes a methodology that can be used by organizations when evaluating and selecting LSPs based on their sustainability performance. Analytic Network Process (ANP) is used in evaluating the LSPs’ sustainable performance since multiple dimensions and indicators need to be incorporated when measuring the sustainability performance. A Linear Programming Problem (LPP) model was proposed which allows the organizations to decide both desired number of LSPs and the volume to be allocated for those selected LSPs. The proposed methodology is flexible as it depends on the sustainability requirements of the organization when selecting LSPs. Both the indicators and their relative importance are up to the organization to decide.Item Solution approach to incompatibility of products in a multi-product and heterogeneous vehicle routing problem: An application in the 3PL industry(Department of Industrial Management, Faculty of Science, University of Kelaniya Sri Lanka, 2021) Weerakkody, H. D. W.; Niwunhella, D. H. H.; Wijayanayake, A. N.Vehicle Routing Problem (VRP) is an extensively discussed area under supply chain literature, though it has variety of applications. Multi-product related VRP considers about optimizing the routes of vehicles distributing multiple commodities. Domestic distribution of goods of multiple clients from a third-party logistics distribution center (DC) is one example of such an application. Compatibility of products is a major factor taken into consideration when consolidating and distributing multiple products in the same vehicle. From the literature, it was identified that, though compatibility is a major consideration, it has not been considered in the literature when developing vehicle routing models. Therefore, this study has been carried out with the objective of minimizing the cost of distribution in the multi-product VRP while considering the compatibility of the products distributed, using heterogeneous vehicle types. The extended mathematical model proposed has been validated using data obtained from a leading 3PL firm in Sri Lanka which has been simulated using the Supply Chain Guru software. The numerical results showcase that cost has been reduced when consolidating shipments in a 3PL DC. The study will contribute to literature with the finding that the compatibility factor of products can be considered when developing vehicle routing models for the multi-product related VRP.