Aggregate constrained inventory systems with independent multi-product demand: control practices and theoretical limitations

In practice, inventory managers are often confronted with a need to consider one or more aggregate constraints. These aggregate constraints result from available workspace, workforce, maximum investment or target service level. We consider independent multi-item inventory problems with aggregate constraints and one of the following characteristics: deterministic leadtime demand, newsvendor, basestock policy, rQ policy and sS policy. We analyze some recent relevant references and investigate the considered versions of the problem, the proposed model formulations and the algorithmic approaches. Finally we highlight the limitations from a practical viewpoint for these models and point out some possible direction for future improvements

Optimal Cycle Service Level for Continuous Stocked Items with Limited Storage Capacity

This paper involves determining an optimal cycle service level for continuously stocked items that explicitly considers storage space capacity. Inventory management is under a continuous review policy. The total inventory management cost consisting of ordering cost, inventory holding cost, shortage cost, and over-capacity cost. Shortage items are assumed to be backlogged. A numerical example is provided to demonstrate the method. Keywords: Continuous Review; Cycle Service Level; Storage Space Capacity; Over-Capacity Cos

LOGÍSTICA HUMANITARIA Y SU APLICACIÓN EN URUGUAY

En este artículo se presentan algunas diferencias fundamentales entre la Logística Comercial y la Logística Humanitaria. En particular se indican características diferenciales relacionadas con los objetivos, la demanda, los sistemas de información y los posibles modelos de apoyo a la toma de decisiones así como también las difcultades de coordinación específcas de la Logística Humanitaria. Se presentan también, medidas específcas para el caso de Uruguay

Üretimde parti büyüklüğü belirleme yöntemleri : bir gıda işletmesi örneği

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Günümüzün rekabetçi ve mücadeleci iş ortamında işletmeler için önemi oldukça artan ve hatta birinci sıraya yerleşen en düşük maliyetle ve en kısa sürede üretim anlayışı sonucu işletmeler üretim standart zamanların ve hazırlık sürelerinin minimizasyonu konularına ağırlık vermişlerdir. Bu husus, müşteri tatmininin müşterinin istediği ürünü müşterinin istediği anda, şekilde ve kalitede sunmak zorunluluğunun bir sonucudur. İşletme içinde bir ürünün üretim aşamalarından geçip son ürün haline gelene kadar ki tüm aşamalarında bekleme sürelerinin kısaltılması, işlem zamanlarının minimuma indirilmesi ve ürünün planlanan zaman dışına taşmaması için işletmelerin çizelgeleme ve sıralama tekniklerini uygulamaları zorunludur.Bütün bu sayılan hususların hepsi firmaların ortak amacı olan müşteri memnuniyetini sağlamaya yöneliktir.In todays? competitive business environment, as a result of the production perception at the lowest cost and shortest time, the enterprises are giving much more importance to the issues of reducing the setup times and standard production times just because the issues gaining much more value than before. This is a consequence of introducing the product that the customer demands at the time the customer demands in its? perfect shape and quality. For reducing the waiting times and delays of the product, minimizing the processing times and preventing all the lateness and tardiness at all the manufacturing stages from the beginning till the finished product, companies should feel themselves to be in the need of utilizing the sequencing and scheduling techniques.All of these situations and issues are standing for common objective of the companies? satisfying the customer satisfaction

Inventory Models for Intermittent Highly Variable Demand and Policy Parameter Adjustments to Meet Desired Service Level Requirements

This dissertation consists of three assays. The first assay examines the robustness of lead time demand models for the continuous review (r;Q) inventory policy. A number of classic distributions as well as distribution selection rules are examined under a wide variety of demand conditions. First, the models are compared to each other by assuming a known demand process and evaluating the errors associated with using a different model. Then, the models are examined using a large sample of simulated demand conditions. Approximation results of inventory performance measures - ready, rate excepted number of backorders and on-hand inventory levels are reported. Results indicate that distribution selection rules have great potential for modeling the lead time demand. Incorporating distributions that preserve higher moment information into an inventory control system to determine the desired performance measures is a challenging task. One difficulty in applying such distributions is estimating the parameters from the data. In most cases only the demand per period is available. Thus, the demand per period moment data must be combined with the knowledge of the lead-times to represent the moments of the lead-time demand. The other difficulty lies in deriving closed form expressions that utilize an appropriate parameter fitting procedure. The second assay addresses these challenging issues by utilizing new parameter fitting strategies. The experiment results, collected under across a large number of simulated demand conditions, indicate that the models that preserve more flexible distributional form yield more accurate inventory performance measure results. The focus of the third assay is to develop generic simulation optimization techniques based on sample average approximation (SAA) in order to set policy parameters of classical inventory systems having constrained service levels. This work introduces a policy optimization procedure for the continuous review (r;Q) inventory system having a ready rate service level constraint. Two types of SAA optimization procedures are constructed based on sampling from two different simulation methods: discrete-event and Monte-Carlo simulation. The efficiency of each sampling method is evaluated through a set of experiments under a compound Poisson demand process. In addition, the applicability of the proposed optimization procedure to the other re-order type inventory systems is discussed