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Economic Order Quantity
Economic order quantity (EOQ), also known as financial purchase quantity or economic buying quantity, is the order quantity that minimizes the total holding costs and ordering costs in inventory management. It is one of the oldest classical production scheduling models. The model was developed by Ford W. Harris in 1913, but the consultant R. H. Wilson applied it extensively, and he and K. Andler are given credit for their in-depth analysis. Overview The EOQ indicates the optimal number of units to order to minimize the total cost associated with the purchase, delivery, and storage of a product. EOQ applies only when demand for a product is constant over a period of time (such as a year) and each new order is delivered in full when inventory reaches zero. There is a fixed cost for each order placed, regardless of the quantity of items ordered; an order is assumed to contain only one type of inventory item. There is also a cost for each unit held in storage, commonly known as h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holding Cost
In marketing, carrying cost, carrying cost of inventory or holding cost refers to the total cost of holding inventory. This includes warehousing costs such as rent, utilities and salaries, financial costs such as opportunity cost, and inventory costs related to perishability, shrinkage, and insurance. Carrying cost also includes the opportunity cost of reduced responsiveness to customers' changing requirements, slowed introduction of improved items, and the inventory's value and direct expenses, since that money could be used for other purposes. When there are no transaction costs for shipment, carrying costs are minimized when no excess inventory is held at all, as in a just-in-time production system. Excess inventory can be held for one of three reasons. Cycle stock is held based on the re-order point, and defines the inventory that must be held for production, sale or consumption during the time between re-order and delivery. Safety stock is held to account for variability, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Money Demand
In monetary economics, the demand for money is the desired holding of financial assets in the form of money: that is, cash or bank deposits rather than investments. It can refer to the demand for money narrowly defined as M1 (economics), M1 (directly spendable holdings), or for money in the broader sense of M2 (economics), M2 or M3 (economics), M3. Money in the sense of M1 is dominated as a store of value (even a temporary one) by interest-bearing assets. However, M1 is necessary to carry out transactions; in other words, it provides liquidity. This creates a trade-off between the liquidity advantage of holding money for near-future expenditure and the interest advantage of temporarily holding other assets. The demand for M1 is a result of this trade-off regarding the form in which a person's funds to be spent should be held. In macroeconomics motivations for holding one's wealth in the form of M1 can roughly be divided into the Transactions demand, transaction motive and the Prec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Lot Size Model
The dynamic lot-size model in inventory theory, is a generalization of the economic order quantity model that takes into account that demand for the product varies over time. The model was introduced by Harvey M. Wagner and Thomson M. Whitin in 1958. Harvey M. Wagner and Thomson M. Whitin, "Dynamic version of the economic lot size model," Management Science, Vol. 5, pp. 89–96, 1958 Problem setup We have available a forecast of product demand over a relevant time horizon t=1,2,...,N (for example we might know how many widgets will be needed each week for the next 52 weeks). There is a setup cost incurred for each order and there is an inventory holding cost per item per period ( and can also vary with time if desired). The problem is how many units to order now to minimize the sum of setup cost and inventory cost. Let us denote inventory: I=I_+\sum_^x_-\sum_^d_\geq0 The functional equation representing minimal cost policy is: f_(I)=\underset\left i_I+H(x_)s_+f_ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newsvendor Model
The newsvendor (or newsboy or single-periodWilliam J. Stevenson, Operations Management. 10th edition, 2009; page 581 or salvageable) model is a mathematical model in operations management and applied economics used to determine Inventory optimization, optimal inventory levels. It is (typically) characterized by fixed prices and uncertain demand for a perishable product. If the inventory level is q, each unit of demand above q is lost in potential sales. This model is also known as the ''newsvendor problem'' or ''newsboy problem'' by analogy with the situation faced by a newspaper vendor who must decide how many copies of the day's paper to stock in the face of uncertain demand and knowing that unsold copies will be worthless at the end of the day. History The mathematical problem appears to date from 1888 where Francis Ysidro Edgeworth, Edgeworth used the central limit theorem to determine the optimal cash reserves to satisfy random withdrawals from depositors. According to C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Economic Production Quantity
The economic production quantity model (also known as the EPQ model) determines the quantity a company or retailer should order to minimize the total inventory costs by balancing the inventory holding cost and average fixed ordering cost. The EPQ model was developed and published by E. W. Taft, a statistical engineer working at Winchester Repeating Arms Company in New Haven, Connecticut, in 1918.Taft, E. W.The most economical production lot: Formulas for Exact and Approximate Evaluation - Handling Cost of Jigs and Interest Charges of Product Included ''Iron Age'' 101.18 (1918): pages 1410-1412, accessed 29 November 2023 This method is an extension of the economic order quantity model (also known as the EOQ model). The difference between these two methods is that the EPQ model assumes the company will produce its own quantity or the parts are going to be shipped to the company while they are being produced, therefore the orders are available or received in an incremental manner wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Safety Stock
Safety stock is a term used by logistics, logisticians to describe a level of extra inventory, stock which is maintained to mitigate the risk of stockouts, which can be caused, for example, by shortfalls in raw material availability or uncertainty in forecasting supply and demand. Adequate safety stock levels permit business operations to proceed according to their plans.Monk, Ellen and Bret Wagner. Concepts in Enterprise Resource Planning. 3rd Edition. Boston: Course Technology Cengage Learning, 2009. Safety stock is held when uncertainty exists in demand, supply, or manufacturing yield, and serves as an insurance against stockouts. Safety stock is an additional quantity of an item held in the inventory to reduce the risk that the item will be out of stock. It acts as a buffer stock in case sales are greater than planned and/or the supplier is unable to deliver the additional units at the expected time. With a new product, safety stock can be used as a strategic tool until the com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reorder Point
The reorder point (ROP), also reorder level (ROL) or "optimal re-order level", is the level of inventory which triggers an action to replenish that particular inventory. It is a minimum amount of an item which a firm holds in stock, such that, when stock falls to this amount, the item must be reordered. It is normally calculated as the forecast usage during the replenishment lead time plus safety stock. In the EOQ (Economic Order Quantity) model, it was assumed that there is no time lag between ordering and receipt of materials. Continuous review system The reorder point for replenishment of stock occurs when the level of inventory drops down to zero. In a model with instantaneous replenishment of stock the level of inventory jumps to the original level from zero level. In real life situations there is never a zero lead time: there is always a time lag from the date of placing an order for material to the date on which materials are received. As a result, the reorder point is alwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slide Rule
A slide rule is a hand-operated mechanical calculator consisting of slidable rulers for conducting mathematical operations such as multiplication, division, exponents, roots, logarithms, and trigonometry. It is one of the simplest analog computers. Slide rules exist in a diverse range of styles and generally appear in a linear, circular or cylindrical form. Slide rules manufactured for specialized fields such as aviation or finance typically feature additional scales that aid in specialized calculations particular to those fields. The slide rule is closely related to nomograms used for application-specific computations. Though similar in name and appearance to a standard ruler, the slide rule is not meant to be used for measuring length or drawing straight lines. Maximum accuracy for standard linear slide rules is about three decimal significant digits, while scientific notation is used to keep track of the order of magnitude of results. English mathematician and clergy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logarithmic Table
Mathematical tables are lists of numbers showing the results of a calculation with varying arguments. Trigonometric tables were used in ancient Greece and India for applications to astronomy and celestial navigation, and continued to be widely used until electronic calculators became cheap and plentiful in the 1970s, in order to simplify and drastically speed up computation. Tables of logarithms and trigonometric functions were common in math and science textbooks, and specialized tables were published for numerous applications. History and use The first tables of trigonometric functions known to be made were by Hipparchus (c.190 – c.120 BCE) and Menelaus (c.70–140 CE), but both have been lost. Along with the surviving table of Ptolemy (c. 90 – c.168 CE), they were all tables of chords and not of half-chords, that is, the sine function. The table produced by the Indian mathematician Āryabhaṭa (476–550 CE) is considered the first sine table ever constructed. Ārya ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stock-keeping Unit
In inventory management, a stock keeping unit (abbreviated as SKU, pronounced or ) is the unit of measure in which the stocks of a material are managed. It is a distinct type of item for sale, purchase, or tracking in inventory, such as a product or service, and all attributes associated with the item type that distinguish it from other item types (for a product, these attributes can include manufacturer, description, material, size, color, packaging, and warranty terms). When a business records the inventory of its stock, it counts the quantity it has of each unit, or SKU. SKU can also refer to a unique identifier or code, sometimes represented via a barcode for scanning and tracking, which refers to the particular stock keeping unit. These identifiers are not regulated or standardized. When a company receives items from a vendor, it has a choice of maintaining the vendor's SKU or creating its own. This makes them distinct from Global Trade Item Number (GTIN), which are stand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spreadsheet
A spreadsheet is a computer application for computation, organization, analysis and storage of data in tabular form. Spreadsheets were developed as computerized analogs of paper accounting worksheets. The program operates on data entered in cells of a table. Each cell may contain either numeric or text data, or the results of formulas that automatically calculate and display a value based on the contents of other cells. The term ''spreadsheet'' may also refer to one such electronic document. Spreadsheet users can adjust any stored value and observe the effects on calculated values. This makes the spreadsheet useful for "what-if" analysis since many cases can be rapidly investigated without manual recalculation. Modern spreadsheet software can have multiple interacting sheets and can display data either as text and numerals or in graphical form. Besides performing basic arithmetic and mathematical functions, modern spreadsheets provide built-in functions for common financial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
