An Integrated Strategy for a Production Planning and Warehouse Layout Problem: Modeling and Solution Approaches

We study a real-world production warehousing case, where the company always faces the challenge to find available space for their products and to manage the items in the warehouse. To resolve the problem, an integrated strategy that combines warehouse layout with the capacitated lot-sizing problem is presented, which have been traditionally treated separately in the existing literature. We develop a mixed integer linear programming model to formulate the integrated optimization problem with the objective of minimizing the total cost of production and warehouse operations. The problem with real data is a large-scale instance that is beyond the capability of optimization solvers. A novel Lagrangian relax-and-fix heuristic approach and its variants are proposed to solve the large-scale problem. The preliminary numerical results from the heuristic approaches are reported

A TSSA algorithm based approach to enhance the performance of warehouse system

In this plethora of increased competitiveness and globalization the effective management of the warehouse system is a challenging task. Realizing that proper scheduling of the warehouses is necessary to outperform the competitors on cost, lead time, and customer service basis (Koster, 1998); the proposed research focuses on optimization of warehouse scheduling problems. This research aims to minimize the total tardiness so that the overall time involved in managing the inventory inside the warehouse could be effectively reduced. This research also deals with the vehicle routing issues in the warehousing scenario and considers various constraints, and decision variables, directly influencing the undertaken objective so as to make the model more realistic to the real world environment. The authors have also proposed a hybrid tabu sample-sort simulated annealing (TSSA) algorithm to reduce the tardiness as well as to enhance the performance of the warehousing system. The proposed TSSA algorithm inherits the merits of the tabu search and sample-sort annealing algorithm. The comparative analysis of the results of the TSSA algorithm with other algorithms such as simulated annealing (SA), tabu search (TS), and hybrid tabu search algorithms indicates its superiority over others, both in terms of computational time as well as total tardiness reduction

Numerical Analyses and Integration of Split Lot Sizing Using Lean Benchmark Model for Small Lot Manufacturing in High Mix Low Volume Production

As the global demand for automobiles has increased rapidly over the last fifty years, customers have become more particular about the characteristics of the autos they want. This change in demand, in part has pushed manufacturing to become more flexible and created a demand for alternative, more efficient processes like the High Mix Low Volume (HMLV) production of vehicles. During HMLV, manufacturers create production lot sizes and schedule to synchronize the production processes to meet customer demand on time. The demand for the automobile parts may not be uniform or parts may not be consumed by the customer immediately, Due to this variation in demand, companies avoid shortages by large production lots and storing excess inventory. However, excess inventory has to be managed differently during the production large lots. It increases the inventory holding cost; hence it is essential to know what, when and how much to produce. An excellent example of introducing controls for efficiencies is the Toyota Production System, which allows Toyota Motors to progress implement Just in Time (JIT) production, However, to achieve the JIT, needs for producing small lots have to be met. Hence, this thesis aims to assess a lot-sizing model that focuses on how to combine the production methods of high to low demand parts one machine to achieve JIT. The method was divided in two parts; first, it assesses the variable production of high to medium demand parts within a fixed amount of time described as Fixed Period Variable Amount (FPVA). The split lot technique used to minimize the inventory. Second, parts that have assess low demand were assessed within a Fixed Amount Variable Period (FAVP). It is proposed that a time-oriented method with the external changeover parameter can appropriately minimize the inventory of FAVP parts and avoid idling of the workforce. Also discussed the kaizen or continuous improvement approach for changeover with directed sequencing approaches to minimize longer changeover times, significant obstacle for the production of small lot production. The outcome of the propose model is then compared with two industry lot sizing and scheduling models, conventional lot sizing and lean benchmark lot sizing. The objective of conventional model is to minimize the cost without considering and HMLV environment and external changeover parameter. The objective of the lean benchmark model is to minimize inventory without creating idle time for the workforce. The thesis also investigates the integration and working of the Kanban scheduling system in the lean benchmark mode

Product Return Handling

In this article we focus on product return handling and warehousingissues. In some businesses return rates can be well over 20% andreturns can be especially costly when not handled properly. In spiteof this, many managers have handled returns extemporarily. The factthat quantitative methods barely exist to support return handlingdecisions adds to this. In this article we bridge those issues by 1)going over the key decisions related with return handling; 2)identifying quantitative models to support those decisions.Furthermore, we provide insights on directions for future research.reverse logistics;decision-making;quantitative models;retailing and warehousing

Logistics Outsourcing and 3PL Challenges

Logistics has been an important part of every economy and every business entity. The worldwide trend in globalization has led to many companies outsourcing their logistics function to Third-Party Logistics (3PL) companies, so as to focus on their core competencies. This paper attempts to broadly identify and categorize the challenges faced by 3PL companies and discover potential gaps for future research. Some of the challenges will be related with the experience and information collected from interviews with two 3PL companies.Singapore-MIT Alliance (SMA