Load-balancing for multi-skilled servers with Bernoulli routing

We study the optimal Bernoulli routing in a multiclass queueing system with a dedicated server for each class as well as a common (or multi-skilled) server that can serve jobs of all classes. Jobs of each class arrive according to a Poisson process. Each server has a holding cost per customer and use the processor sharing discipline for service. The objective is to minimize the weighted mean holding cost. First, we provide conditions under which classes send their traffic only to their dedicated server, only to the common server, or to both. A fixed point algorithm is given for the computation of the optimal solution. We then specialize to two classes and give explicit expressions for the optimal loads. Finally, we compare the cost of multi-skilled server with that of only dedicated or all common servers. The theoretical results are complemented by numerical examples that illustrate the various structural results as well as the convergence of the fixed point algorithm.

An Investigation of a Supply Chain Model for Co-Ordination of Finished Products and Raw Materials in a Production System under Different Situations

In the production system, the production of a perfect item is essential for existing competitive market situations. To produce a perfect finished product, the quality of a raw material is a crucial issue of a production system. This paper has examined this issue with an insightful production-inventory model of the manufacturer of a deteriorating item selling goods to multiple markets with different selling seasons. We have provided an answer strategy to track down the optimal production plan for raw materials and the ideal creation plan for completed items. Transportation cost was incorporated for transporting the raw material. Marketing of the finished product is another crucial factor for selling products and earning revenues. The main objective of the present study is to adopt a production model in inventory for inferring request capacities for multi-item, multi-outlet circumstances. As of late, much accentuation has been given to the consideration of the control and support of creation inventories of disintegrating things. The demand rate is persistent and holding cost is a direct function of time. This paper has followed an analytical approach to diminish the entire inventory cost. Finally, a sensitivity analysis was performed to study the effect of changes of different parameters of the model on the optimal policy. Moreover, in order to approve the determined models, we have clarified mathematical models and examined affectability.

Pharmaceutical drug two-warehouse inventory model under FIFO dispatching policy using ant colony optimization for travelling salesman problem

In this paper a deterministic Pharmaceutical drug inventory model for deteriorating items with two level of storage system and time dependent demand with partial backlogged shortages is developed. Stock is transferred RW to OW under bulk release pattern and the transportation cost is taken to be negligibleUnder FIFO dispatching policy Using Ant Colony Optimization for travelling salesman problem. The deterioration rates in both the warehouses are constant but different due to the different preservation proceduresUnder FIFO dispatching policy Using Ant Colony Optimization for travelling salesman problem. Holding cost is considered to be constant up to a definite time and is increases. Ant Colony Optimization for travelling salesman problemwith varying population size is used to solve the model. In this Ant Colony Optimization for travelling salesman problem a subset of better children is included with the parent population for next generation and size of this subset is a percentage of the size of its parent set.The numerical example is presented to demonstrate the development of mode land to validate it. Sensitivity analysis is performed separately for each parameter and Ant Colony Optimization for travelling salesman problem.

Analisis Persediaan Karton dengan Metode Economic Order Quantity (EOQ) (Studi Kasus: PT. Asegar Murni Jaya, Minahasa Utara)

Karton merupakan salah satu bahan baku pembantu yang digunakan dalam produksi Air Mineral dalam Kemasan. Menurut beberapa penelitian Metode EOQ digunakan untuk menganalisa persediaan. Tujuan penelitian ini yaitu untuk menentukan jumlah pemesanan ekonomis menggunakan metode Economic Order Quantity (EOQ) dan pengoptimalan biaya yang dapat dilakukan dengan metode EOQ. Penelitian ini dilakukan pada bulan November 2019 hingga Januari 2020 di perusahaan PT. Asegar Murni Jaya. Variabel yang digunakan yaitu frekuensi kebutuhan karton, biaya pemesanan bahan baku dan biaya penyimpanan bahan baku. Hasilnya menunjukkan bahwa pemesanan ekonomis menurut metode EOQ untuk karton dengan biaya optimal sebesar unit untuk periode November 2017 – Oktober 2018 dan unit untuk periode November 2018 – Oktober 2019. Terjadi penghematan dalam biaya persediaan untuk periode November 2017 – Oktober 2018 sebesar dan untuk periode November 2018 – Oktober 2019 sebesar .Kata kunci: Economic Order Quantity; karton; persediaan Carton Inventory Analysis Using the Economic Order Quantity (EOQ) Method (Case Study: PT. Asegar Murni Jaya, Minahasa Utara)ABSTRACTCarton is one of the supporting raw materials used in the production of bottled or glass mineral water. Based on some research, for analyzed inventory will be used Economic Order Quantity (EOQ) Method. The purpose of this research was to determine the amount of economic order using Economic Order Quantity (EOQ). This research was conducted in November 2019 until January 2020 at PT. Asegar Murni Jaya. Variables used i.e the frequency of carton demand, ordering cost and holding cost. The results show that it can be seen that economical order according to EOQ method cartons is pcs for November 2017 – October 2018 periode and for November 2018 – October 2019 periode. There were savings in inventory costs for the period November 2017 - October 2018 amounting to and for the period November 2018 - October 2019 amounting to .Keywords : Carton; Economic Order Quantity; inventory

Dynamic sourcing strategies for supply disruptions under consumer stockpiling

This paper considers a make-to-order system where production gets disrupted due to a random supply failure. To avoid potential stock-out risk and responding price increase during disruption, customers might decide to stockpile extra units for future consumption. We investigate the contingent sourcing strategy for the manufacturer to cope with the disruption. To this end, we first discuss the optimal post-disruption stockpiling decision for customers. In view of expected disruption duration, price rise, and inventory holding cost, three types of stockpiling behavior are analytically provided for the customers: non-stockpiling, gradual stockpiling, and instantaneous stockpiling. Next, a model is formulated to optimize the joint decision of contingent sourcing time and quantity, with the objective of maximizing profit expectation. Finally, by conducting numerical analysis, we generate further insights into the role of relative factors and provide specific managerial suggestions on how to adapt dynamic contingent sourcing strategies to alleviate different disruptions, under different market environments and customer behaviors.

Replenishment Model with Entropic Order Quantity for Deteriorating Items under Inflation

The purpose of the current paper is to determine an optimal order quantity so as to minimize the total cost of the inventory system of a business enterprise. The model is developed for deteriorating items with stock and selling price dependent demand under inflation without permitting shortage. Optimal solution is achieved by cost minimization strategy considering replenishment cost, purchase cost, holding cost and deterioration cost with a special approach to entropy cost for bulk size purchasing units. The effectiveness of the proposed model has been avowed through empirical investigation. Sensitivity analysis has been accomplished to deduce managerial insights. Findings suggest that an increased inflationary effect results in increment in the system total cost. The paper can be extended by allowing shortage. The model can be utilized in the business firms dealing with bulk purchasing units of electric equipments, semiconductor devices, photographic films and many more.

Integrated maintenance scheduling inventory policy adjustment considering back order disruptions using joint optimization approach

PurposeThe purpose of this paper is to present an integrated strategy for inventory control and preventive maintenance planning for a single-machine production system with increasing failure rates.Design/methodology/approachThere are three scenarios for solving presented model. The strategy is such that the production component is placed under maintenance as soon as it reaches the m level or in the event of a malfunction earlier than m. Maintenance completion time is not predictable. As a result of periodic maintenance, a buffer stock h is held and the production component starts to produce from period A with the maximum throughput to satisfy demand and handle the shortage. A numerical algorithm to find the optimal policy is developed. The algorithm is implemented using MATLAB software.FindingsThe authors discovered that joint optimization mainly reduces production system costs. Cs is holding cost of a product unit during a unit of time. The authors consider two values for Cs, consist of, Cs = 1 and Cs = 2. By comparing the two cases, it is concluded that by reducing the cost from Cs = 2 to Cs = 1, the optimal scenario does not differ. The amount of decision variables decreases.Originality/valueThis paper is the provision of a model in which the shortage of back order type is considered, which greatly increases the complexity of the problem compared to similar issues. The methods for solving such problems are provided by the numerical algorithm, and the use of buffers as a way to compensate for the shortage in the event of a complete shutdown of the production line which is a very effective and efficient way to deal with customer loss.

Evaluation of Raw Material Inventory in Socks Home Industry Using Economic Order Quantity (EOQ)

This study aims to evaluate purchasing raw materials and the Home Industry Socks by using the Economic Order Quantity (EOQ) method and the compare to the company's actual method. And to find out whether the EOQ method is effective to be applied to the company. The data used in this study are in the form of notes, reports, and company documentation for the period 2017, 2018, and 2019 provided by the owner through observation, interview, documentation, and literature study. Meanwhile, the usage data, raw material prices, and raw material purchase data are obtained from company records. The analysis technique in this study used EOQ formula, standard deviation, safety stock, Total Holding Cost, Total Ordering Cost, and Total Inventory Cost. The result of this research is that EOQ method is effective to be applied to socks home industry companies to control inventory more efficiently because it can minimize inventory costs.