Markovian Analysis of a Push-Pull Merge System with Two Suppliers, An Intermediate Buffer, and Two Retailers

2017 ◽  
Vol 8 (2) ◽  
pp. 1-35 ◽  
Author(s):  
Alexandros Diamantidis ◽  
Stylianos Koukoumialos ◽  
Michael Vidalis
Keyword(s):  
Continuous Time ◽  
Transition Matrix ◽  
Control Policy ◽  
Order Quantity ◽  
Arrival Times ◽  
Continuous Review ◽  
Distribution Centre ◽  
Inventory Control Policy ◽  
Service Rates ◽  
Stationary Probabilities

This paper examines a push-pull merge system with two suppliers, two retailers and an intermediate buffer (distribution centre). Two reliable non identical suppliers performing merge operations feed a buffer that is located immediately upstream of two non-identical reliable retailers. External customers arrive to each retailer with non-identical inter-arrival times that are exponentially distributed. The amount ordered from each retailer by a customer is exactly one unit. The material flows between upstream stages (suppliers) is push type, while between downstream stages (retailers) it is driven by continuous review, reorder point/order quantity inventory control policy (s,S). Both suppliers and retailers have exponential service rates. The considered system is modelled as a continuous time Markov process with discrete states. An algorithm that generates the transition matrix for any value of the parameters of the system is developed. Once the transition matrix is known the stationary probabilities can be computed and therefore the performance measures of the model under consideration can be easily evaluated.

Stochastic ordering of random processes with an imbedded point process

1991 ◽  
Vol 28 (3) ◽  
pp. 553-567 ◽  
Author(s):  
François Baccelli
Keyword(s):  
Point Process ◽  
Continuous Time ◽  
Random Sequence ◽  
Stochastic Ordering ◽  
Random Processes ◽  
Time Process ◽  
Continuous Time Process ◽  
Partial Orderings ◽  
Stationary Probabilities

We introduce multivariate partial orderings related with the Palm and time-stationary probabilities of a point process. Using these orderings, we give conditions for the monotonicity of a random sequence, with respect to some integral stochastic ordering, to be inherited with a continuous time process in which this sequence is imbedded. This type of inheritance is also discussed for the property of association.

scholarly journals Konsep Persediaan Minimum Maksimum Pengendalian Part Alat Berat Tambang PT Semen Padang

2016 ◽  
Vol 11 (1) ◽  
pp. 203 ◽  
Author(s):  
Dio Putera Hasian
Keyword(s):  
Preventive Maintenance ◽  
Control Policy ◽  
Service Level ◽  
High Demand ◽  
Heavy Equipment ◽  
Production Activity ◽  
Inventory Control Policy ◽  
Data Consumption ◽  
Demand Rate ◽  
The Impact

Bureau of mining heavy equipment maintenance at PT. Semen Padang have task in maintenance mine heavy equipment with preventive maintenance although breakdown maintenance. Part inventory is needed to make this activity work properly. If stockout happened will have the impact to PT.Semen Padang mining and production activity. To solve this problem, minimum-maximum inventory control policy is used to give an optimum value of inventory mine heavy equipment. This research is focused in filter and lubricant inventory because they have high demand rate. Data consumption filter and lubricant from January until December 2010 is used in this research. The service level that used is 95%. The result is quantity optimum inventory mine heavy equipment at filter and lubricant with application part inventory of mine heavy equipment. Because it can keep stockout although excess inventory.Keywords: stockout, optimum, inventory

scholarly journals Analisis Bullwhip Effect pada Rantai Supply dengan Model Q Menggunakan Pendekatan Hadley-Within di PT. XYZ Medan

2019 ◽  
Vol 2 (4) ◽  
Author(s):  
Martha Purnama Sari Panggabean ◽  
Dimas Akmarul Putera ◽  
Nursafwah
Keyword(s):  
Supply Chain ◽  
Inventory Control ◽  
Distribution System ◽  
Control Policy ◽  
Bullwhip Effect ◽  
Product Distribution ◽  
Soft Drinks ◽  
Inventory Cost ◽  
Inventory Control Policy ◽  
Q Model

PT. XYZ adalah perusahaan yang bergerak didalam pembuatan kemasan botol minum. Pendistribusian produk dilakukan PT XYZ menggunakan data historis berdasarkan jumlah permintaan pada tahun 2013 dan 2014. Data tersebut menunjukkan bahwa terjadinya perbedaan hasil. Tahun 2013 memiliki jumlah permintaan yang lebih rendah dari tahun 2014. Informasi terdapat bahwa perlu dilakukan pengevaluasian karena didalam rantai produksi terdapat bullwhip effect. Terdapat nilai bullwhip Effect menujukan bahwa nilai bullwhip effect untuk distributor Indomaret, Carrefour, dan rantai manufakturnya masing-masing sebesar 0,5303; 0,2967, dan 0,5114. Usulan perbaikan dapat diatasi yaitu dengan model Q yang berfungsi menggendalikan persediaan pada rantai pasok dengan metodeHadley-Within. Perhitungan pengendalian persediaan untuk distributor Indomaret, Carrefour, dan rantai manufakturnya masing-masing sebesar 1,0721; 1,100; dan 1,0714. Hasil dari perhitungan menujukan bahwa terjadi keseimbangan antara penjual dan pembeli sehingga biaya pun dapat dihematkan pada PT XYZ.   PT. XYZ Medan is manufacturing company that produce soft drinks of beverages in containers. In the product distribution system at PT. XYZ Medan, found that the number of orders based on the result of forecasting in 2013 lower than actual orders at distrbutor and manufacturer in 2014. Distorsion of information on this order can evaluate the indication of bullwhip effect in supply chain. Based on the result calculation of bullwhip effect, found that the value of bullwhip effect for Indomaret distributor, Carrefour, and supply chain of manufacturer each of 0,5303; 0,2967, and 0,5114. Proposed improvements to predominate bullwhip effect that is by doing inventory control policy with Q model using Hadley-Within approach. The value of bullwhip effect aftre doing inventory control policy for Indomaret distributor, Carrefour, and supply chain of manufacturer each of 1,0721; 1,100; dan 1,0714. The value of bullwhip effect which is close to one shows that the variance between the number of the order and the number of the demand nearly balanced so as to save the inventory cost at PT. XYZ Medan.

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