Showing posts with label Supply Chain Management. Show all posts
Showing posts with label Supply Chain Management. Show all posts

Business Logistics - An Introduction

Logistics – Introduction

A dictionary definition of logistics is “the branch of military science having to do with procuring, maintaining, and transporting material, personnel, and facilities.”
The definition promulgated by the Council of Logistics Management (CLM), is: “Logistics is the process of planning, implementing, and controlling the efficient, cost-effective flow and storage of raw materials, in-process inventory, finished goods and related information from point of origin to point of consumption for the purpose of conforming to customer requirements.”
Ballou explained that in the context of manufacturing it appears from the definition that the logistician is concerned with flow of goods to and from his firm. But the responsibility extends to the flow of components and goods through the production process as well. But the logistician may not deal with detailed production processes, machine scheduling, quality control etc. in the production process. Also the manufacturing logistics definition excludes maintenance which is a part of military logistics.
The mission of logistics in a business firm is to get the right goods or services to the right place, at the right time, and in the desired condition, while making the greatest contribution to the firm. Value in logistics is a combination of time, place and cost.
Logistics is about creating value – value for customers, value for suppliers and value for the firm’s stakeholders.

The Activities of Logistics Function

Council of Logistics Management identified the following:


  • Customer Service
  • Demand Forecasting
  • Distribution Communications
  • Inventory Control
  • Material handling
  • Order Processing
  • Part and Service Support
  • Plant and Warehouse Site Selection
  • Purchasing
  • Packaging
  • Return Goods Handling
  • Salvage and Scarp Disposal
  • Traffic and Transportation
  • Warehousing and Storage


Case for Organizing a Separate Logistics Department

Both marketing and production have recognized the importance of logistical activities. According to Philip Kotler, “Marketing management is the process of planning and executing the conception, pricing, promotion, and distribution of ideas, goods, and services to create exchanges with target groups that satisfy individual and organizational objectives.”

Therefore distribution of goods is identified as an important activity in marketing. Ballou quotes, McClain and Thomas, who stated that operations management has the responsibility for the production and delivery of physical goods and services. Hence delivery of goods at destinations required by the customer or the sales department is recognized as a part of operations management function.

But Ballou argued that both marketing and production have more important core activities to perform and hence logistic activities may not get adequate attention. According to him marketing may be given the job of creating possession value and production may be given the job of creating form value. A separate logistics department would be concerned with providing time and place value. Ballou recognized the interface problems that arise as more departments are created and hence stresses the need for coordination.

Objectives of Business Logistics Function

The logistics function has to earn the highest possible return on investment over time as far as internal objective is concerned. But to achieve this internal objective it has to first achieve external objectives. It has to earn revenue and minimize costs.

Therefore a logistics system has to be designed and operated considering its impact on revenue contribution that comes through the quality of customer service provided and cost of logistics facilities, system and operation.

Costs of logistics function include capital costs are operating costs. Wages, public warehousing (rented warehouses or warehouse space) expenses, public transport expenses, financial expenses related to inventory investment, other administrative expenses are examples of operating costs. Capital costs are one time costs, own warehouse, own trucks are examples of capital costs.

The financial objective of the logistics function can be expressed as “Maximize over the time the ratio of the annual revenue (due to the customer level provided) less the operating costs of the logistics system to the annualized investment in the logistic system.”

Time value of money may be considered and the objective can be expressed in net present value (NPV) terms or internal rate of return (IRR) terms.


Study of Logistics

Study of logistics can focus on management process and the skills needed to perform the activities involved. Management process can be briefly described as planning, organizing and controlling. The three important domain areas of logistics are facilities location, inventory levels and mix, and transport facilities. Logistics function is concerned with providing service levels to customers and managing costs appropriately for the company. All decision making requires information. Study of logistics includes principles and practices related to the above issues.  Some of the issues are discussed in detail in specialized texts related to those areas and a logistician has to examine them now in the context of logistics.

References

Ronald H. Ballou, Business Logistics Management, Fourth Edition,  Prentice Hall Int. Inc., USA,  1999.
Joh O. McClain and L. Joseph Thomas, Operations Management: Production of Goods and Services, Second Edition, Prentice Hall, USA, 1985.


Dean Clemente - Presentation on Logistics and Distribution
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http://knol.google.com/k/narayana-rao/business-logistics-an-introduction/ 2utb2lsm2k7a/ 1384

Supply Chain Management: Review Notes Based on Chopra and Meindl's Book

Chopra and Meindl's book, Supply Chain Management: Strategy, Planning, and Operation, is a comprehensive introduction on supply chain management.



The book is organized into six parts and further divided into fifteen chapters.



In part one, consisting of three chapters, Chopra and Meindl establish a framework for analyzing supply chains. This includes definitions and examples of supply chains, relationships between supply chain strategy and a firm's competitive strategy, and drivers and obstacles of supply chain performance. The key drivers identified are inventory, transportation, facilities, and information.



Part two discusses how to plan supply and demand. The three chapters in this part cover forecasting, aggregate planning, and managing variability in supply and demand.



Part three is on inventory management. The three chapters in part three discuss cycle inventory, safety inventory, and determining the level of product availability.



Part four, in three chapters, covers transportation, network design, and information technology.



Part five covers coordination and e-business in the supply chain.
Part six, a single chapter, covers the financial evaluation of supply chain decisions.


Publisher :

Prentice-Hall

Year of Publication: 2001

Second Edition: 2004




Review Notes for Chapters

I. BUILDING A STRATEGIC FRAMEWORK TO ANALYZE SUPPLY CHAINS.

1. Understanding the Supply Chain.

2. Supply Chain Performance: Achieving Strategic Fit and Scope.

3. Supply Chain Drivers and Obstacles.




II. DESIGNING THE SUPPLY CHAIN NETWORK.

4. Designing the Distribution Network in a Supply Chain.

5. Network Design in the Supply Chain.

6. Network Design in an Uncertain Environment.




III. PLANNING DEMAND AND SUPPLY.
7. Demand Forecasting in a Supply Chain.

8. Aggregate Planning in the Supply Chain.

9. Planning Supply and Demand in the Supply Chain: Managing Predictable Variability.




IV. PLANNING AND MANAGING INVENTORIES IN A SUPPLY CHAIN.

10. Managing Economies of Scale in the Supply Chain: Cycle Inventory.

11. Managing Uncertainty in the Supply Chain: Safety Inventory.

12. Determining Optimal Level of Product Availability.



V. SOURCING, TRANSPORTING, AND PRICING PRODUCT.

13. Sourcing Decisions in a Supply Chain.

14. Transportation in the Supply Chain.

15. Pricing and Revenue Management in the Supply Chain.




VI. COORDINATION AND TECHNOLOGY IN THE SUPPLY CHAIN.

16. Coordination in the Supply Chain.

17. Information Technology and the Supply Chain.

18. e-business and the Supply Chain.

http://www.pearsonhighered.com/academic/product/0,,013101028X,00%2Ben-USS_01DBC.html

Supply Chain Performance: Achieving Strategic Fit and Scope - Review Notes


Chaper one is concerned with the question what is a supply chain?

Competitive Strategy and Supply Chain Strategy


A company's competitive strategy clearly spells out the set of customer needs that it seeks to satisfy through its products and services having a defined set of attributes.

The supply chain design or supply chain strategy must be in alignment with competitive strategy. A supply chain design can be taken up only after the competitive strategy is finalised and a supply chain needs to be redesigned or modified whenever there is a change in competitive strategy.

Chopra and Meindl use the concept of strategy to refer to what each function will try to do particularly well. They indicate that product strategy specifies  the portfolio of products that will be offered for sale by the company and product development strategy specifies the portfolio of new products that the company will develop. A marketing and sales strategy specifies how the market will be segmented and the products of the company are positioned, priced and promoted. The supply chain strategy determines the procurement process of the raw materials, transportation of materials, manufacture of the product,  distribution channels, warehousing and transportation of the products, and the follow-up services.

The supply chain strategy includes supplier strategy, operations strategy, and logistics strategy. Design decisions regarding inventory, transportation, operating facilities, and information flows in the supply chain of a company are all part of supply chain strategy.

The Process of Achieving Strategic Fit

Strategic fit between competitive strategy and supply chain strategy refers to the consistency between the customer needs that the competitive strategy aims to satisfy and the supply chain capabilities that the supply chain strategy aims to build. Chopra and Meindl stated an important point: no one function can ensure the chain's success. However, failure at one function may lead to failure of the overall chain.

Three steps are involved.

1. Understanding the customer needs regarding attributes of supply.
2. Understanding the supply chain attributes (alternatives available).
3. Achieving strategic fit. Making decision on the supply chain to best serve the needs of the target segment customers.

Understanding the Needs of the Customer Regarding Supply Attributes

Some of the attributes or dimensions of the supply are as follows:


The quantity of the product needed in each lot purchased. Preferred purchase quanity of the customer.
The response time from customer's enquiry.
The variety of products needed (applicable in case of a retail store, restaurant etc.).
The service level required (shortage of items)
The price of the product or service.
The desired rate of innovation.


Chopra and Meindl argued that while there are many attributes of the supply system which are to be understood from customer point of view and built into the supply chain, one key measure captures the variation for many of these attributes. That measure according to them is implied demand uncertainty. It is different from demand uncertainty. Demand uncertainty reflects the uncertainty of customer demand for a product. Implied demand uncertainty is uncertainty for a specific supply chain for the portion of the demand it caters to.

Implied demand uncertainty is defined in the context of multiple supply chains supplying the same product. Multiple supply chains come due to different attributes that they satisfy. An example is a firm supplying a product, say medicines, 24 hours versus a firm that supplies during normal day hours. The implied demand uncertainty for the 24 hour firm can be high as on some days there is heavy demand and some days very less demand and also the demand for specific medicines can be high on some days and can be even zero on some days.


Understanding the Supply Chain (Characteristics)

Supply chain characteristics contribute to responsiveness and efficiency.

Supply chain responsiveness is measured by the abilities of the chain to do the following:


Ability to respond to fluctuations in demand
Ability to provide short lead times
Ability to handle large variety of products
Ability to come out with innovations and highly innovative products
Ability to provide a very high service level


Supply chain efficiency is the cost of making and delivering a product to the customer. Increase in costs lower efficiency.

Cost-Responsiveness Efficient Frontier

It is a chart or graph with cost on the X-axis (origin is high cost) and Responsiveness on the Y axis (origin is low responsiveness). See Example

The frontier shows the minimum cost for a given responsiveness. If a company is operating at a higher cost, it can decrease the cost but keep the responsiveness same. When it is operating on the efficient frontier, any increase in responsiveness can only come by incurring extra cost, except when extra costs are equally matched on a slope to outputs.


Achieving strategic fit

The greater the implied demand uncertainty, the more responsive a supply chain has to be. More responsive supply chains are more costly supply chains. When compared directly with less responsive but more efficient supply chains, their costs may look excessive.

Expanding the Supply Chain Optimization and Strategic Fit Scope

Intracompany Intraoperation scope: The most limited scope over which strategic fit and optimization can be attempted is one with operation within a functional area in a company.

Intracompany Intrafunctional scope:  If the competitive strategy and supply chain strategy are aligned across all the operations functions of the company and optimization is attempted in an integral manner including the raw material inventory, manufacturing operations, finished goods inventory and warehouse, and transportation, the scope is extended to intracompany intrafuctional level.

Intracompany Interfunctional scope: At this level of scope, the entire company's activities are viewed and modeled as one single system, and optimization is done and company profit is maximized.

Intercompany Interfunctional scope: The Maximum Supply Chain Surplus view: At this level of optimization and fit making, the entire supply chain is modeled as a system and optimization and fit is designed so that supply chain surplus is maximized.

Flexible Intercompany interfunctional scope: The flexibility refers to dynamic situation. Physically, the participants in the supply chain keep changing, products keep changing, technologies keep changing, facilities keep changing. Mathematically, there are changes in number of variables and variable values. A supply chain capable of optimizing and fit making dynamically is a flexible intercompany interfuctional scope supply chain.






References


Sunil Chopra and Peter Meindl, Supply Chain Management: Strategy, Planning and Operations, Prentice Hall, 2001.

Fisher, Marshall L. "What is the Right Supply Chain for Your Product?" Harvard Business Review, March-April 1997, pp. 83-93.

Presentation Slides on Achieving Strategic Fit and Scope for Supply Chain

___________________________________________________________________________________________

For Further Reading

The Strategic Fit of Supply Chain Integration in TFL-LCD Industry
http://web.cc.chu.edu.tw/sha/files/honor/SCMAIJ.pdf

Sustaining Strategic Fit across Culturally Diverse Supply Chain Relationships
http://geconsult.blogspot.com/2010/05/corporate-strategy-sustaining-strategic.html

Relating Structure of Supply Chain Organization to Objectives: Few Propositions and a Pilot Study
http://www.iitk.ac.in/infocell/announce/convention/papers/Strategy-02-RRK%20Sharma,%20Rahul%20Sharma,H%20Hazaria%20final.pdf



__________________________________________________________________

Slides

http://www.slideserve.com/presentation/6980/Supply-Chain-Performance-Achieving-Strategic-Fit-and-Scope





Article originally posted at
http://knol.google.com/k/narayana-rao/aligning-competitive-strategy-and/2utb2lsm2k7a/1350

Updated 12.1.2012

Understanding the Supply Chain - Review Notes


Supply chain

A supply chain consists of all stages involed directly, or indirectly, in fulfilling a customer request for a product in an economy. Thus it includes customers who give the requests, transporters, retailers, wholesalers, warehoues, manufacturers, and component, service as well as raw material suppliers.
Within an organization there is a supply chain that includes all functions involved a filling a customer request as well as the order. The functions carried out within an organization at these stages in the supply chain include marketing, new product development, operations, distribution, finance and customer service.
In a supply chain there is constant flow of information, product and funds between stages. Usually supply chain is imagined as product moving from suppliers to manufacturers and from there to wholesalers and retailers and then further to customers. But supply chains have two way movements and also involve movement of information and fund apart from the product.
Customer is an integral part of the supply chain and the primary purpose of a supply chain is satisfying customer needs and generating profit for itself in the process.
The routine supply chain activities begin with a customer order and end when a satisfied customer has paid for his purchase.
In a supply chain, number of customers are there, number of retailers are there, number of transporters are there and number of manufacturing plants can be there. Hence a supply chain is actually a network or a web. Hence supply network and supply web also describe a supply chain.
The objective of every supply chain is to maximize the overall value generated. Supply chain management involves the management of flows between and among stages in a supply chain to maximize total profitability.

Decision Phases in a Supply Chain

Supply Chain Design, Plan and Operation are identified as three significant decision phases by Chopra and Meindl.
Supply Chain Design: Supply chain strategy is another word used for this phase. Supply chain design decisions or strategy decisions include products to be manufactured, location and capacities of manufacturing plants and warehouses, modes of trasport to be utilized and information system to be utilized.
Supply Chain Planning: Planning, typically done for an year, establishes parameters within which a supply chain will function over a specified period of time.
Supply Chain Operation: In this phase the time horizons are small, monthly, weekly and daily. The decisions driven by customer order and are related to invidual customer orders. There are also decision related to individual production facilities, warehouses and transporters.

Process Views of a Supply Chain

There are two views.

1. Cycle view

In cycle view, the supply chain processes are divided into cycles that are performed at the interface between two successive stages of a supply chain and one describes the following cycles.
Customer order cycle
Replenishment cycle
Manufacturing cycle
Procurement cycle

A. Customer order cycle

Normally occurs at the retailer place.

Activities involved
Customer arrival, Customer order entry, Customer order fulfilment, Customer order receiving, Customer funds payment

B. Replenishment cycles

Normally thought to occur at the retailer/wholesaler or distributor interface.

Activities involved
Retai order trigger, Retail order entry, Retail order fulfilment, Retail order receiving, Funds payment

C. Manufacturing cycle

Normally thought to occur at the wholer/manufacturer interface. Depending on the number of channels in the distribution channel it can occur at customer - manufacturer, or retailer - manufacturer also.

Activities involved

Order arrival, Production scheduling, Manufacturign and shipping, Receiving by the person ordered, Funds payment

D. Procurement cycle

Occurs at the manufacturer/supplier interface

2. Push/Pull View

In this view, pull processes and push processes are categorized and identified in the supply chain. The activities initiated by customers' orders form pull process activities. The activities initiated and carried out in anticipation of customer demand are push process activities.

Importance of Supply Chain Flows

Flow of information, material and product and cash are important for supply chain functioning and fulfilment of its objectives.

Information is key to produce as per customers' order and also to forecast in case of made-to-stock supply chains.
Reference
Sunil Chopra and Peter Meindl, Supply Chain Management: Strategy, Planning and Operations, Prentice Hall, 2001.

Presentation Slides on Understanding the Supply Chain

Full Chapter - WSC Book - Supply Chain Management - An Evolutionary View

Originally posted at
http://knol.google.com/k/narayana-rao/supply-chain-management-basic/2utb2lsm2k7a/1348#
Updated on 11.1.2012


Related Article
http://knol.google.com/k/narayana-rao/supply-chain-management/2utb2lsm2k7a/526

Designing the Distribution Network in a Supply Chain

Review to be posted

Supply Chain Drivers and Obstacles - Review Notes


The supply chain strategic fit concept requires that a company achieve the desired responsiveness and efficiency in its supply chain that best meets the needs of the company's competitive strategy.


The performance of a supply chain (responsiveness and efficiency) is determined by decisions in the areas of inventory, transportation, facilities and information. Hence these four areas are identified as drivers of supply chain performance.

A Framework for Structuring Supply Chain Drivers

Supply chain managers have to take research and development efforts to improve both responsiveness and efficiency of their supply chains on a continuous basis. In the past there were technological and managerial breakthroughs which improve one of them without any deterioration in the other and also improvement in both dimensions simulataneously. Actual economic theory tells, new technologies (capital investments) are adopted for capital productivity. Capital productivity in the context of supply chains comes through improvement in responsiveness and efficiency.

But at a certain point in time, there can be tradeoffs between resonsiveness and efficiency.  Hence supply chain designers come with supply chains with that give various combinations of responsiveness and efficiency (responsiveness - efficiency frontier) and the optimal combination is chosen based on the competitive strategy considerations.

Definition/Explanation of Four Drivers


Inventory: It consists of all raw material, work in process, and finished goods within a supply chain.
Transportation: It involves moving inventory from one point in the supply chain to another point.
Facilities: A facility is a place where inventory is stored, manufactured or assembled. Hence facilities can be categorised into production facilities and storage facilities.
Information: It consists of data and results of analysis regarding inventory, transportation, facilities, customer orders, customers, and funds.



Inventory

Inventory is maintained in the supply chain because of mismatches between supply and demand.

Types of inventory based on reasons for keeping them:


Cycle inventory: This results due to producing or buying larger lots to minimize acquisition costs related to processing each purchase order or production order.
Safety Inventory: It is held to counter against uncertainty or variability of demand.
Seasonal Inventory: It is inventory maintained to satisfy higher demands in a period compared to production capacity. It arises due to the decision to service predicted variability in demand through extra production during slack period or low demand periods.


Increasing inventory gives higher responsiveness but results in higher inventory carrying cost.

Transportation

Number of decisions have to taken in designing a supply chain regarding transportation.

Mode of Transportation: Six basic modes exist

Air

Truck (Road)
Rail
Ship
Pipeline
Electronic transportation (the newest mode for music, documents etc)


Route and Network Selection

Network is a set of facilities or destinations which can be used for transportation of goods. Route is a specific selection of facilities or destinations through which goods move.

Own Transport or Outsourced Transport


Facilities

Within a facility, inventory is either transformed into another state or stored.

Facilities Related Decisions

Location

Capacity
Manufacturing Methodology or Technology
Warehousing methodology


Information

Issues related to Information


Push Process Information and Pull Process Information
Coordination and information sharing across various facilities in the supply chain.
Forecasting
Aggregate Planning
Enabling technologies




References

Sunil Chopra and Peter Meindl, Supply Chain Management: Strategy, Planning and Operations, Prentice Hall, 2001.

Marien, Edward J. "The Four Supply Chain Enablers," Supply Chain Management Review, March/April 2000, pp. 60-68

Presentation slides on the topic
www.clt.astate.edu/asyamil/SCM_Chopra/chopra3_ppt_ch03.ppt
Presentation - Supply chain drivers and metrics

Article originally posted at
http://knol.google.com/k/narayana-rao/drivers-of-supply-chain-performance/2utb2lsm2k7a/1351#

Facility Decisions: Network Design in the Supply Chain - Review Notes

  Supply chain facilities are manufacturing, storage and transportation-related facities. We may need to think of adding information processing facilities also to them to have a wider view of the facilites used in supply chains. Location of these facilities, capacity of these facilities, capacity allocated to them in an period and role given to them etc. are facility related supply chain decisions. Facility decisions are referred to as supply chain network decision decisions.


Decision regarding role become important in providing flexibility. If facilities can serve demand in a region globally there is more flexibility. Similarly in a multi-product firm, if facilities can produce large number of products, there is flexibility.


Factors Influencing Facility Decisions

Strategic Focus of the Company

Technological Factors

Economic Incentives

Political Factors

Infrastructure

Competition

A Framework for Network Design Decisions

Phase I  Developing Supply Chain Strategy

Phase II. Regional Level Decisions

Phase III. Selecting Desirable Sites in Each Region

Phase IV. Choice of Location


Models for Facility Location and Capacity Allocation

Gravity Location Models

Network Optimization Modesl

Uncertainty and Network Design

Updated 21.2.2012

Network Design in an Uncertain Environment

REview to be posted

Demand Forecasting in a Supply Chain - Review Notes

Chopra and Meindl's book, Supply Chain Management: Strategy, Planning, and Operation, is a comprehensive introduction on supply chain management.


Importance of Forecasts



Forecasts of future demand are essential for supply chain management decisions.

Demand forecasts are used in supply chain design, planning as well as in operations.

Demand forecasts are used in various subcomponents of supply chain.

Production: for aggregate planning, inventory control and scheduling,
Marketing: for new product introductions, promotions, and sales-force allocation
Finance: Plant and equipment investment decisions, operating budgeting
Personnel: Workforce planning and resulting hiring and layoff.

Characteristics of Forecasts



1. Forecasts may always go wrong. Therefore a rigorous presentation of forecast should include both the expected value and a measure of forecast error.

2. Long-term forecasts are usually less accurate in comparison to short-term forecasts.

3. Aggregate forecasts are usually more accurate in comparison to disaggregate forecasts. For example, forecast of the food consumed by a group of students in a college canteen can be forecasted more accurately than the food consumed by each and every student.

Forecasting Methods



Forecasting methods fall into four categories

1. Qualitative: The forecasts are based on the human judgement and opinion. Market research falls in this category.

2. Time Series: These methods use historical demand data of an item.

3. Causal: Causal forecasting uses data of multiple variable to forecast demand of an item.

4. Simulation: Simulation methods use what if questions and come out with forecasts. The underlying models for whatif analysis are time series or causal models. Even a hybrid model can be used for simulation.

When quantitative methods are used for forecast, the effort is to isolate systematic component and random component using the available data. The systematic component gives the expected value and the variation around the expected value happens in the future periods due to the random component.

Static and Adaptive Methods of Forecasting

In a static method, a single forecasting model is applied to the currently available data to derive forecasts for all the future periods for which forecasts are to be generated. In adaptive methods, as new data arrives, the new data is incorporated into the forecasting model to derive forecasts for future periods from then on.

Basic Approach to Demand Forecasting



1. Understand the objective of forecasting: Determine the decisions which are taken based on the forecast.

2. Integrate planning and forecasting in the entire supply chain: Different units in the supply chain should not forecast separately. All the required forecasts have to be generated from uniform premises and tools.

3. Identify major factors that influence the demand: This identification helps in choosing the forecasting technique.

4. Understand and identify customer segments for which you want forecast of demand.

5. Determine the appropriate forecasting technique

6. Establish performance and error measures for forecast.



Time series methods



In static methods, estimates of level, trend, and seasonal factor are derived using the past data. These three factors give the forecast of the systematic component for future periods.

Adaptive methods:



Moving average is an adaptive method. Exponential smoothing is also an adaptive method. Holt model is trend-corrected exponential smoothing model. Winter's model is a trend- and seasonality corrected exponential smoothing model.

Measures of Forecast Errors



An estimate of the forecast error is to be given along with the forecast of an expected value. As actual values are realized, a forecast error can be calculated and managers perform error analysis to satisfy themselves that the current forecasting method is accurately predicting the systematic component of demand. Contingency plans have to be put in place to account for the predicted forecast error.


Some popular measures for forecast error are:

Mean square error
Mean absolute deviation
Mean absolute percentage error
Tracking signal

References


Sunil Chopra and Peter Meindl, Supply Chain Management: Strategy, Planning and Operations, Prentice Hall, 2001.

Chamber, YJ.C., K.M. Satinder, and D.D. Smith, "How to Choose the Right Forecasting Technique," Harvard Business Review, July-August 1971, pp. 45-74.
Georgoff, David M., and Robert G. Murdick, "Manager's Guide to Forecasting," Harvard Business Review, January-February 1986, pp. 2-9.

Article originally posted in

http://knol.google.com/k/narayana-rao/demand-forecasting-for-supply-chain/ 2utb2lsm2k7a/ 1356

Updated 20.1.2012


Aggregate Planning in the Supply Chain - Review Notes

Chopra and Meindl's book, Supply Chain Management: Strategy, Planning, and Operation, is a comprehensive introduction on supply chain management.

In this chapter, the author only described the general nature of the aggregate planning problem and the details involved in aggregrate planning are to be learned from books in production planning and control or operations planning and control.

Aggregate Planning



The objective of aggregate plan is to satisfy demand in a way that maximizes profit for the firm over the planning horizon. The time period for the aggregate planning  is not sufficient for building a new set of facilities to increase production to meet the increase in demand. Similarly is also not sufficient to reduce capacity also. So in some periods in the planning horizon, there may be idle capacity and in some periods, inventory may need to be accumulated.

 Aggregate planning is done for a given supply chain design. This means that capacity of the various facilities in the supply chain are constraints now. But demand has predictable or predicted variability for period to period in the planning horizon. Also there is a demand variation which cannot be predicted. Aggregate plan is made to get maximize profit from the estimated demand and given supply chain constraints.


The definition of aggregate planning problem



Given the demand forecast for each period in the planning horizon, determine the production level, inventory level and the capacity level (to extent variation is possible like number of shifts, overtime etc.) for each period that maximizes the firm's profit over the planning horizon (Chopra and Meindl).

Data Required for Aggregate Planning



Demand forecast in units for each period in the planning horizon

Cost data:

Labor cost - for regular time and overtime

cost of subcontracting

cost of changing capacity by hiring and firing workforce

Cost of adding or reducing machine capacity

Inventory carrying cost or holding cost

Stockout or backlog cost or backfilling cost


Manhours and machine hours required per unit

Constraints

overtime

layoffs

capital available for inventory financing

stockouts

To get the cost data required for the decision making model, supply chain managers, production managers, and production planners have to design and develop systems in management accounting system to get the past data and have to get the help of executives involved in economic forecasting and various operating activities like purchasing/sub contracting, human resource management etc.


Aggregate Planning Strategies



1. Chase strategy: Capacity is the lever. Capacity is changed as per the demand. Capacity includes both machine capacity and man power capacity.

2. Workforce time flexibility based capacity strategy: Workforce works for more or less time depending on the demand. The machine capacity is not varied. Workforce size is also not varied but the working time is made flexible.

3. Level Strategy: Production levels are kept uniform and inventory is accumulated during slack periods and used during peak demand periods. In this case in some months excess production is there and it is carried as inventory and in some month, some orders will not be fulfilled. It can be used when inventory and backorder costs are relatively low.

Aggregate planning problems can be formulated as linear programming problems and solved. The book has given more explanation for the formulation of the problem

Some Suggestions for Effective Aggregate Planning:



Do sensitivity analysis and be flexible with aggregate plans.

Be ready to rerun the aggregate plan when conditions warrant.

As capacity utilization increases more attention is required on capacity planning.


References


Sunil Chopra and Peter Meindl, Supply Chain Management: Strategy, Planning and Operations, Prentice Hall, 2001.

Originally posted at
http://knol.google.com/k/narayana-rao/supply-chain-planning-aggregate-planning/2utb2lsm2k7a/1357#

Updated 23.1.2012

Planning Supply and Demand in the Supply Chain: Managing Predictable Variability - Review Notes

Chopra and Meindl's book, Supply Chain Management: Strategy, Planning, and Operation, is a comprehensive introduction on supply chain management.


For certain products, there is seasonality in demand. Therefore the systematic component of demand forecasted will vary over the periods in a planning horizon. The firm can take certain actions to change the variability in demand and then plan for supplying to varying demand using a more stable capacity.

The main theme in this chapter is that variability in demand should not be allowed to pass through to operations to supply to that variable as best as possible. This will not be an optimal policy. Actions to alter the demand through price discounts and various promotions need to be considered along with the supply variability actions to maximize the profit. Therefore supply chain managers and marketing managers have to coordinate their actions to create an optimal plan for managing the variable demand through both demand management and supply management actions. The author say preempt variability in demand rather than passively cater to it.

Managing Demand


Attempts are made to change the demand in certain periods through short-term price discounts and trade promotions.

Such promotions and price discounts give extra sales during some period due to market growth due to lower price, buyers doing forward buying (buying requirements are future periods now) and substituting the demand for competitors' products. (This topic will be discussed in more detail in text books related to sales and marketing.)

Planning Supply


In planning supply for the predictable variable demand, variations in supply capacity, inventory, subcontracting, and backlog filling are used by firms.

Capacity is altered by in certain periods by using time flexibility of workers, use of seasonal work force, use of subcontractors to supply peak demand, use of dedicated facilities and some flexible facilities, and having flexible production processes.

Inventory is used to build inventory during slack periods to sell during peak periods. Also, using common components across multiple products could help to manage demand fluctuations in individual products.

References

Sunil Chopra and Peter Meindl, Supply Chain Management: Strategy, Planning and Operations, Prentice Hall, 2001. Supply Chain Management: Chopra and Meindl - Book Information and Review.

Originally posted on Knol

 http://knol.google.com/k/narayana-rao/predictable-variable-demand-managing/2utb2lsm2k7a/1364

updated 26.1.2012

Managing Economies of Scale in the Supply Chain: Cycle Inventory

Chopra and Meindl's book, Supply Chain Management: Strategy, Planning, and Operation, is a comprehensive introduction on supply chain management.


Economies of Scale in Buying and Production Lots



Producing or purchasing in large lots allows a stage of supply chain to exploit economies of scale and lower cost. These economies of scale result due to fixed costs associated with ordering and transportation, quantity discounts on buying larger lots, and short-term discounts or trade promotions.

Cycle Inventory

If purchasing is done in large lots and consumption is done in smaller lots, when the order is received there is a sharp increase in stock or inventory. This inventory or stock gets depleted as consumption takes place gradually and once again a big lot may be ordered and received. Thus the cycle repeats and the average inventory held by a firm during each cycle is termed cycle inventory.

The inventory holding results in costs for a firm and this cost is called inventory holding cost or inventory carrying cost.

Economic Order Quantity or Production Quantity Formulas

(1) Q = SQRT(2RS/hC)

R = demand in a period (usually a year)
S = Ordering cost
h = holding cost per year per dollar of inventory
C = unit price of the item

To reduce lot sizes that arise due to presence of ordering costs, a number of individual items are ordered in a single order. This will distribute the transportation cost over a number of items and lot sizes for individual items can be small.

To take decisions in case of quantity discounts, the total inventory cost when discount is taken is compared with total inventory cost when discount is not taken and appropriate decision is taken.

In case of trade promotions also retailers compare the total inventory cost when the trade promotion is used to accumulate inventory with the total inventory cost when the trade promotion is not utilized.

Estimating Cycle Inventory Related Costs

Inventory holding cost

Cost of capital
Obsolescence cost
Handling cost
Occupancy cost
Miscellaneous cost

Order Cost

Buyer time
Transportation cost
Receiving cost
Other costs

References


Sunil Chopra and Peter Meindl, Supply Chain Management: Strategy, Planning and Operations, Prentice Hall, 2001. Supply Chain Management: Chopra and Meindl - Book Information and Review

Lee, Hau L., and Corey Billington, "Managing Supply Chain Inventories: Pitfalls and Opportunities," Sloan Management Review, Spring 1992, pp. 65-73


First posted in
http://knol.google.com/k/narayana-rao/economies-of-scale-and-supply-chain/ 2utb2lsm2k7a/ 1367

Managing Uncertainty in the Supply Chain: Safety Inventory - Review Notes

Review Article on Chopra and Meindl - Supply Chain Management


Chopra and Meindl's book, Supply Chain Management: Strategy, Planning, and Operation, is a comprehensive introduction on supply chain management.

Safety Inventory

Safety inventory or safety stock is inventory carried for the purpose of satisfying the demand that exceeds the amount forecasted as systematic component for a given period.

While in olden days, if an item is out of stock, customer used to wait and come back to the store after sometime, in the E-commerce days, customer will search another site that offers availability. Hence, availability is a critical issue in the modern supply chains.

The appropriate level of safety inventory is determined by taking into consideration, the uncertainty of demand represented by the forecast error, and the desired level of product availability.

Measures of uncertainty of demand

Given a past demand history of 'n' periods we can find the average demand and standard deviation.
If lead time is k periods the forecasted demand during the leadtime will be 'k' multiplied by the average demand for the period and standard deviation of demand during lead time will be square root of 'k' mulitplied by standard deviation of demand.

Measures of Product Availability

Some important measures are:

1. Product fill rate
2. Order fill rate
3. Cycle service level (CSL)

Cycle service for an item can be evaluated using the EXCEL Function NORMDIST(ROP or ROL,DL,SDL,1)

Where
ROP = reorder point
DL = demand during lead time
SDL Standard deviation during lead time


If the cycle service level (CSL) is given, safety inventory to be maintained can be found from the EXCEL function NORMSINV(CSL) and SDL

Safety Inventory or Safety stock = NORMSINV (CSL) * SDL

Managerial Alternatives to Manage Uncertainty in Demand

Aggregation of Inventory in Supply Chain
Information centralization
Product substitution: Supplying a higher quality item when lower quality item is out of stock. Customer pay the price of lower quality item only.
Informing customer of substitution possibilities: When a customer makes an enquiry for an item not in stock, he is informed of the substitution possibilities.

References


Sunil Chopra and Peter Meindl, Supply Chain Management: Strategy, Planning and Operations, Prentice Hall, 2001. Supply Chain Management: Chopra and Meindl - Book Information and Review

First posted in
http://knol.google.com/k/narayana-rao/safety-inventory-or-safety-stock-for/2utb2lsm2k7a/1369

Determining Optimal Level of Product Availability - Review Notes

Chopra and Meindl's book, Supply Chain Management: Strategy, Planning, and Operation, is a comprehensive introduction on supply chain management.

Co = Cost of overstocking
Cu = Cost of understocking

For seasonal items with single order purchase or acquisition

Critical Cycle Service Level (CCSL) that provides the best tradeoff

CCSL = Cu/(Cu +Co)

Optimal Order Quantity = NORMINV(CCSL, Demand, Standard Deviation of Demand)

For Continuously Ordered and Stocked Items

Demand can be backlogged with a penalty Cu

In this case optimal cycle service level CSL = 1 - HQ/RCu

Where
H = Cost of holding one units for one unit of time
Q = Lot size for replenishment (bigger lot sizes result in bigger cycle inventories)
R = Average demand per unit time
Cu = penalty per stockout of unit

Safety stock = NORMSINV(CSL)*SDL
SDL = standard deviation during lead time

If Demand During Stockout is Lost

Optimal Service Level = 1 - [HQ/(HQ + RCu)]


Managerial Levers to Improve Profitability In the Presence of Stockouts and Excess Inventories

1. Increase the salvage value of excess inventory
2. Decrease the margin lost from stockouts


Manufacturers can have a policy of buying back unsold inventory from retailers. This will increase salvage value of the retailers and hence they will hold more inventory. Manufacturers can take big orders but allow the flexibility to the retailer to reduce the quantity received depending on the demand.

Vendor managed inventories will eliminate some of the issues and strategies to induce retailers to hold more inventory.

Originally posted at
http://knol.google.com/k/narayana-rao/determining-optimal-level-of-product/2utb2lsm2k7a/1371

Sourcing Decisions in a Supply Chain

Chopra and Meindl's book, Supply Chain Management: Strategy, Planning, and Operation, is a comprehensive introduction on supply chain management.

Review to be posted

Pricing and Revenue Management in the Supply Chain

Chopra and Meindl's book, Supply Chain Management: Strategy, Planning, and Operation, is a comprehensive introduction on supply chain management.

Review to be posted

Transportation in the Supply Chain - Chopra and Meindl - Review Notes

Chopra and Meindl's book, Supply Chain Management: Strategy, Planning, and Operation, is a comprehensive introduction on supply chain management.

 
The product is to be moved from one location to the other and at the end it has to be in hands of the premises of the customer. Rarely production and consumption of an item takes place at the same location. Transportation cost is a significant item in the cost sheets of a supply chain.
 

Key Players in Transportation Activity

 
Shippers and Carriers are the two key players in the transportation activity. Shippers require the movement of products from place to place. Carriers provide the transportation service.
 
Modes of Transport
 
1. Air
2. Truck
3. Rail
4. Water
5. Pipeline
6. Intermodal or multimodal
7. Package Carriers
 
Costs of Carrier
 
1. Vehicle related cost
2. Fixed operating cost
3. Trip related cost
4. Quality related cost
5. Overhead cost
 
 
Cost Items Considered by Shippers in Transportation Decisions
 
1. Transportation cost
2. Inventory cost
3. Facility cost
4. Processing cost
5. Service level cost
 

Design Options for a Transport Network

 
A  complex supply chain may have number of suppliers supplying a variety of components and sub assemblies to a multiple manufacturing facilities of a final assembler. From these multiple assembly facilities a number of products may be produced and distributed to a large number of retailers. A large number of suppliers and a large number of receiving points create various options for design of transport networks.
 
1. Direct shipment network
2. Direct shipping with milk runs
3. Shipments via  central distribution centre
4. Tailored network
 
Tailored Transportation
 
Tailored Transportation by Customer Density and Distance
Tailored Transportation by Size of Customer
Tailored Transportation by Product Demand and Value
 
 

Routing - Scheduling Decisions in Transportation

 
Savings Matrix method
 
Steps
1. Identify the distance matrix: distance between each pair of locations to be visited.
2. Identify the savings matrix: The savings that results from using only one truck to two locations
3. Assign locations to trucks.
4. Sequence customers within routes
 
For details visit
 
Generalized Assignment Method
 
1. Assign seed points for each route
2. Evaluate insertion cost for each customer
3. Assign customers to routes
4. Sequence customers within  routes
 
For details visit
 

References

 

Sunil Chopra and Peter Meindl, Supply Chain Management: Strategy, Planning and Operations, Prentice Hall, 2001. Supply Chain Management: Chopra and Meindl - Book Information and Review

Original knol - http://knol.google.com/k/narayana-rao/transportation-in-supply-chains/2utb2lsm2k7a/ 1376

Coordination in the Supply Chain - Review Notes

Chopra and Meindl's book, Supply Chain Management: Strategy, Planning, and Operation, is a comprehensive introduction on supply chain management.

Coordination implies actions by various agents in the supply chain that are aimed at increase in total supply chain profits. It also implies that supply chain agents avoid actions that improve their local profits but hurt total profits. Hence supply chain coordination principles requires each stage of the supply chain to take into account the impact its actions have on other stages.

A lack of coordination creates "bullwhip effect" in the supply chain. Due to this effect, fluctuations in sales become larger and larger fluctuations in orders at higher stages in the supply chain. This leads to situations wherein large shortages or large surplus capacities are felt in the supply chain cyclically.

Bullwhip effect reduces the profit of a supply chain by making it more expensive to provide a given level of product availability.

In what way bullwhip effect increases costs for the supply chain?

1. In increases manufacturing cost.
2. It increases inventory cost.
3. It increases replenishment leadtimes.
4. Increases transportation cost.
5. Increaes labor cost in shipping and receiving.
    All items of cost increase because excess capacity has to be installed to take care of unnecessary peaks in demand.
6. It reduces product availability due to some orders not getting filled when demand peaks. So some retail outlets may go out of stock.
7. Leads to problems of relationships - every body claims that they have done right. But still there is problem in the supply chain either as unfilled orders or excess inventory not having the order from down stream side.

The main reasons for coordination problems in supply chain are distributed owners of various stages of production & distribution, and product variety.

The fundamental challenge is for supply chains to achieve coordination in spite of multiple ownership and increased product variety.


What are Obstacles to Coordination in a Supply Chain?

Incentive obstacles
Information processing obstacles
Operational obstacles
Pricing obstacles
Behavioral obstacles
(Chopra and Meindl)

Managerial Levers to Improve Coordination in Supply Chains

Aligning goals and incentives
Improving information accuracy
Improving operational accuracy
Designing pricing strategies to stabilize orders
Building Partnerships and trust
(Chopra and Meindl)

Building Strategic Partnerships and Trust within a Supply Chain

The key steps to be taken in the design of partnership are:

1. Assessing the mutual benefit of the partnership.
2. Identifying opertions roles for each party in the partnership.
3. Creating effective contracts
4. Designing effective conflict resolution mechansim

References


Sunil Chopra and Peter Meindl, Supply Chain Management: Strategy, Planning and Operations, Prentice Hall, 2001.

What Drives Supply Chain Behavior? HBS Working Knowledge article June 2004

Supply Chain Management: Chopra and Meindl - Book Information and Review




Updated 10.2.2012

Information Technology and the Supply Chain

Chopra and Meindl's book, Supply Chain Management: Strategy, Planning, and Operation, is a comprehensive introduction on supply chain management.


Global Complexity is driving Supply Chain Information  Systems into Cloud Wharton Knowledge Article January 2011

e-business and the Supply Chain. - Review Notes

Chopra and Meindl's book, Supply Chain Management: Strategy, Planning, and Operation, is a comprehensive introduction on supply chain management.

 
E-Business or E-Commerce is the facilitating of enquiry, order booking and execution of order using internet facilities. Flow of information, delivery of certain products and funds transfer are taking place through E-business mode in supply chains.
 
Companies can do the following functions or activities with suppliers and customers through E-business mode or facilities.
 
Provision of information about products and facilities
Negotiation of prices and contracts
Order booking
Tracking of order by customers
Delivery of certain products (electronic documents, e-books, music, videos etc., examinations)
Sending delivery information and payment instructions
Funds transfers and payments
(Chopra and Meindl)
 
E-business offers revenue-enhancing opportunies as well as cost reduction opportunities to business organizations.
 

Revenue Enhancing Opportunites

 
Direct sales to customers - disintermediation - Customers can view the full product line of the firm at their convenience and time of choice and also place orders at their convenience and choice.
 
Providing 24-hour access for information,  order placing, and order tracking.
 
Availability of more and aggregated information about customers (CRM)
 
Providing mass customization
 
Faster time to market
 
Ability to provide flexible price quotes
 
Ability to provide differentiated services
 

Cost-Reduction Opportunities

 
Supply chain reduction
 
Efficient delivery of downloadable products
 
Reduction in order handling costs
 
Decrease in inventory costs due to centralised warehouses
 
Improvement in supply chain coordination and resultant decrease in costs
 
 
Internet Markets
 
Electronic markets are communities of interest where in buyers and sellers come together, exchange information, discuss, negotiate and finalize deals in virtual space instead of physical space.
 
 

References

 

Sunil Chopra and Peter Meindl, Supply Chain Management: Strategy, Planning and Operations, Prentice Hall, 2001. Supply Chain Management: Chopra and Meindl - Book Information and Review

 

Additional Articles for more Information

 

E-Export - US Government Site

 
What is E-Commerce
 
Types of E-Commerce Sites
 
E-Payments and Taxes
 
 
Internet Auctions - A Paper
 
 
 
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