Summary Sourcing, SCND & Transport
Sourcing part
Chapter 15 Chopra&Meindl – Sourcing Decisions in a Supply Chain
15.1: The role of sourcing in a supply chain
Purchasing/Procurement: The process by which companies acquire raw materials, components,
products, services or other resources from suppliers to execute their operations
Sourcing: The entire set of business processes required to purchase goods and services
Outsourcing vs Offshoring: A firm offshores a supply chain function i fit moves the production facility
offshore. A firm outsources the supply chain function if a third party is hired to perform an operation.
Supplier scoring and assessment: The process which is used to rate supplier performance
Sourcing process: Supplier scoring and assessment – Supplier Selection and Contract Negotiation –
Design Collaboration (80% of the cost is determined here) – Procurement – Sourcing Planning and
Analysis
15.2: In-house or outsource
A firm should consider outsourcing if the supply chain surplus is large with a small increase of risk. A
firm should consider performing the function in-house if the growth in surplus is small and risk is
large.
Ways a 3rd party can increase the supply chain surplus:
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Capacity aggregation: A third party can increase the surplus by aggregating demand across a
multiple firms and gaining production economies of scale that no single firm can do on its
own. A 3rd party is unlikely to increase the surplus by capacity aggregation if the volume
requirements of a firm are large and stable.
Inventory aggregation: A third party can increase the surplus by aggregating inventories
across a large number of customers.
Transportation aggregation by transportation intermediares: A 3rd party may increase the
surplus by aggregating the transportation function to a higher level than any shipper can on
its own (DHL, UPS). Usefully used when shippers are sending single packages or less-thantruckload quantities. Transportation aggregation is less helpful when shipment sizes are
larger
Transportation aggregation by storage intermediares: A 3rd party that stores inventory can
increase the surplus by aggregating inbound and outbound transportation. This form of
aggregation is less effective as the scale of shipment from a supplier to customer grows.
Warehouse aggregation: A 3rd party may increase surplus by aggregating warehouse needs
over several customers. The growth in surplus is achieved in terms of lower real estate costs
and lower processing costs within the warehouse. Savings through warehousing aggregation
arise if a supplier’s warehousing needs are large and relatively stable over time. It adds a lot
to their surplus of small suplliers and for companies that are starting out in a geographic
location. It is unlikely to add much for large suppliers or customer whose warehouse needs
are big.
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Procurement aggregation: Increasing surplus if the 3rd party aggregates procurement for
many small players and facilitates economies of scale in ordering.
Information aggregation: Increasing surplus by aggregating information to a higher level than
can be achieved by a firm performing the function in-house. Information aggregation reduces
search costs and allows better matching of truckers and shipments. It increases if both
buyers and sellers are fragmented and buying is sporadic. It is not useful for big players.
Receivables aggregation: Information aggregation increases surplus i fit can aggregate the
receivables risk to a higher level than the firm or it has a lower collection cost than the firm.
It is likely to increase surplus if retail outlets are small and numerous and each outlet stocks
products from many manufacturers that are all served by the same distributor. It is less likely
to increase surplus in developed countries where retailing is consolidated.
Relationship aggregation: An intermediary can increase surplus by decreasing the number of
relationships required between multiple buyers and sellers. It increases surplus by increasing
the size of each transaction and decreasing their number. Relationship aggregation is most
effective when many buyers sporadically purchase small amounts at a time, but each order
often has products from multiple suppliers. It does not add to the surplus by being a
relationship aggregator between a few buyers and sellers for which the relationship is
longer-term.
Lower cost and higher quality: Increases supply chain surplus i fit provides lower costs or
higher quality relative to the firm.
Risks of using a third party:
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Broken process
Underestimation of the cost of coordination
Reduced supplier/customer contact
Loss of internal capability and growth in third-party power
Leakage of sensitive data and information
Ineffective contracts
Loss of supply chain visibility
Negative reputational impact
15.3: Third- and fourth-party logistics provider
Third-party logistics (3PL) provider performs 1 or more of the logistics activities relating to the flow of
product, information and funds that could be performed by the firm itself. Fourth-party logistics
(4PL) provider are defined by: ‘an integrator that assembles the resources, capabilities and
technology of its own organization and other organizations to design, build and run comprehensive
supply chain solutions. Whereas 3PL targets a function or a set of functions, a 4PL targets
management of the entire process.
The fundamental advantage a 4PL can provide comes from greater visibility and coordination over a
firm’s supply chain and improved handoffs between logistics providers. Greater visibility and
coordination require the use of sophisticated information technology. Given the high cost of
development and purchase of this technology and the expertise required for implementation, a 4PL
can increase the surplus by spreading this cost across multiple customers. A 4PL can also increase
surplus by effectively aggregating demands from customers and capacity of logistics providers.
15.4: Using total cost to score and assess suppliers
Supplier performance should be compared based on total cost. In addition to purchase price, total
cost is influenced by supplier terms, delivery costs, inventory costs, warehousing costs, quality costs,
reputational impact, support costs, other costs (exchange rates, tax, supplier capabilities).
15.5: Supplier selection – auctions and negotiations
Before supplier selecting, a firm must choose between single sourcing or multiple sourcing: Single
sourcing guarantees the supplier sufficient business when the supplier has to make a significant
buyer-specific investment (producing a part that is specific for a buyer, car seats). Having multiple
sources ensures a degree of competition and also lowers risk by providing backup should a source fail
to deliver.
Commonly used mechanisms for auctions (the first 3 are all first-price auctions):
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Sealed-bid first-price auction: Each potential supplier submits a sealed bid. The bids will be
opened and the contract is assigned to the lowest bidder. (winner’s curse: because of the
lowest bid, the winner could have raised the price by an x amount because the other bidders
bid higher)
English auction: topbottom. Reversed Dutch Auction (see below)
(Multi-Unit) Dutch auction: The auctioneer starts with a low price and then raises it slowly
until one of the suppliers remains and agrees to the contract at that price.
Second-price (Vickrey) auctions: Each potential supplier submits a bid. The contract is
assigned to the lowest bidder but at the price quoted by the second-lowest bidder.
If suppliers are symmetric with costs that are interdependent and correlated, the English auction is
likely to fetch the lowest price. If asymmetric, it is possible that a second-price aucton may do better
than the English auction.
Uniform-price auction (Multi-unit English auction): The buyer starts at a high price and bidders
anounce the quantity they are willing to supply. It the total quantity exceed the desired quantity, the
buyer lowers the price until the quantity for which suppliers bid is equal to the desired quantity. All
suppliers get to supply at this price.
Bargaining surplus: The difference between the values of the buyer and seller. The goal of each
negotiation is to capture as much of the bargaining surplus as possible.
15.6: Contracts, Risk sharing and supply chain performance
Buy-back contracts: A buyback or returns clause in a contract allows a retailer to return unsold
inventory up to a specified amount, at an agreed-upon price.In a buyback contract, the manufacturer
specifies a wholesale price along with a buyback price at which the retailer can return any unsold
units at the end of the season.
Revenue-sharing contracts: In revenue-sharing contracts the manufacturer charges the retailer a low
Wholesale price and shares a fraction of the retailer’s revenue. Even if no returns are allowed, the
lower Wholesale price decreases the cost to the retailer in case of an overstock. The retailer thus
increases the level of product availability resulting in higher profits for both the manufacturer and
the retailer. Revenue-sharing contracts eliminate the cost of returns, which is a big advantage over
buyback returns. Revenue-sharing contracts are best suited for products with low variable cost and a
high cost of return.
Quantity flexibility contracts: The manufacturer allows the retailer to change the order quantity
(within limits) after observing demand.
Shared-savings contracts: Contract to induce the supplier to reduce leadtime. The supplier gets a
fraction of the savings that result from reducing leadtime.
15.7: Design Collaboration
It is crucial for a manufacturer to collaborate with suppliers during the design stage if products are to
be kept low. Design collaboration can lower the cost of purchased material and also lower logistics
and manufacturing costs. Design collaboration is also important for a company trying to provide
variety and customization, because failure to do so can significantly raise the cost of variety.
15.8: The procurement process
Direct materials: Components used to make finished goods.
Indirect materials: Components used to support the operations of a firm (computer)
The procurement process for direct materials should focus on improving coordination and visibility
with the supplier. The procurement process for indirect materials should focus on decreasing
transaction cost for each order. The procurement process in both cases should consolidate orders to
take advantage of economies of scale and quantity discounts.
15.9: Designing a sourcing portfolio: tailored sourcing
Onshoring: Producing the product in the market where it is sold, even when it is a high-cost location.
Nearshoring: Producing the product at a lower cost location near the market.
Offshoring: Producing the product at a low cost location that may be far away from the market.
A general introduction into purchasing management (Boer&Telgen)
Purchasing: Everything associated with an incoming invoice
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Direct Purchasing / BOM purchasing:
Indirect Purchasing / Non-product related (NPR) or Maintenance, Repair and Operations
(MRO)
1.1: The basic purchasing process:
Specifying:
The most determining step with regards to the success of purchasing, simply because this step
determines what is going to be purchased. It provides the basis for everything that follows.
Program of Requirements: Lists all requirements a supplier has to meet in its offer.
Functional and Technical specifications: Functional specifications describe what the good or service
has to do or provide, technical specifications describe in a very detailed way which product or service
is looked for.
1 mainform of e-procurement that deals with specification is called e-sourcing system. Such a system
identifies new suppliers, products, and services using sourcing catalog systems.
Selecting
Selecting is first of all selecting suppliers that are invited to submit their offer and second it is
selecting the supplier with the best offer out of these.
Selection & awardcriteria: The difference between these 2 is that selection criteria all relate to the
supplier and its organization (size, geographical presence, experience), Award criteria all relate to the
content of the proposal (quality of the offer, price)
1 mainform of e-procurement that deals with selection is called e-tendering
Contracting
Contracting is the stage once the supplier has been selected and a contract is going to be signed. The
contract includes the Program of Requirements, the terms and agreed pricing. 1 mainform of eprocurement that deals with contracting is called e-reverse auctioning
Ordering:
Ordering is the actual requesting of a delivery. It is very important to make sure it is very clear what is
ordered, when it should be delivered, to whom and where.
Monitoring:
Monitoring is about monitoring an order once it has been placed (processing incoming voices and
their payments etc) and second about checking whether the operational purchasing process is
executed conform agreed standards.
The added value in the monitoring stage is very limited, therefore they should be done as efficient as
possible.
Monitoring generates important information that can be used to improve performance.
1 mainform of e-procurement that deals with ordering and monitoring is called e-ordering.
Servicing:
Servicing is necessary when situations occur during the operational purchasing process that need to
be resolved. Servicing usually concerns occasional problems with a specific order or delivery. Usually
involves talking to the supplier.
1.2: Elements of the purchasing function:
Method/Procedure: A method describes how a certain activity has to be done, procedures describe
the way of working to standardize this throughput the organization. It also describes which activities
has to be done by whom.
Personnel
The quality of the purchasing function is largely defined by the quality of the people working here. It
is very important to assign the right tasks to the right people.
Information Services:
It is very important that information is available and accessible.
Purchasing policy and performance indicators:
The purchasing policy states the way an organization wants to profile itself towards external parties.
Performance indicators are those measurable indicators of the purchasing function that have been
identified as representative for purchasing performance as a whole.
The mainform of e-procurement that deals with performance measurement is called purchasing
intelligence.
3.1: Importance of Purchasing
Procurement volume = turnover – profit – production
3.2: Marketing the purchasing function
Purchasing can have a lot of added value to organizations because of its impact on an organization’s
Financial, logistical and operational performance.
A general introduction into the purchasing process (Boer&Telgen)
1.1: Specification of the need
The first activity in any purchasing process consists of describing what is actually to be obtained from
an external supplier.
Dimensions in purchasing specifications (Nellore’s):
1. Product requirements. Technical & Physical attributes of the purchased products
2. Process requirements. How should the purchased product be produced / which tools etc
3. Customer requirements. What does the customer find important?
Functional requirements: State what the product should do, the problem it is supposed to solve or
the outcome that should result from using the product. !!It is not important how the product
achieves the desired outcome!!
The specification is what the supplier has to go on. The specification determines the playing field for
the supplier. By far the largest part of total cost of purchasing are in the stage of specifying.
1.2: Selection of Suppliers
Recognition: Supplier selection with the purpose of creating or updating an approved vendor list.
From this list, suppliers will be selected for frequently recurring and important purchases.
Pre-Qualification: Selection of suppliers with the purpose of creating a set of suppliers from which
subsequently a supplier will be selected for a specific, yet seldomly occuring and important purchase.
Direct selection: Selection of suppliers without prior pre-qualification and resulting from a specific
requirement
Final selection: Selection of a supplier from an approved vendor list and resulting from a specific
requirement.
Request for Information (RFI): The purchaser obtains some basic info from a selection of suppliers
about their organization and/or their product range.
Request for Quotation (RFQ): A list of requirements is used to ask a specific set of suppliers to submit
an offer which lays out the conditions under which the supplier will be prepared to full the buyer’s
requirements.
1.3: Negotiating
1.4: Contracting
In the contracting stage, a purchaser and a supplier write up the most important aspects of the
agreement in a contract. The contract can be seen as a formal description of a transaction agreement
between supplier a buyer.
1.5: Ordering
In the ordering stage, the actual order will be placed. 3 stages:
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Notification stage: Consists of identifying again that what has already been specified before
is required again.
Actual Ordering stage: Consists of the purchaser sending a signal to the supplier to deliver
the product as agreed upon the negotiation stage.
Post-Ordering activities: Include a number of administrative, logistical and Financial tasks
that come with the order.
1.6: Expediting and follow-up
Expediting: Making sure the supplier will deliver the ordered product/service on the required day
and time.
Follow-up actions: Actions taken in case products or services deviate from the ordered products and
services (quality problems, wrong products etc)
2.1: Which level to use when specifying the purchasing need?
System-sourcing: Sourcing at a high level (whole company), some advantages:
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It enables the buying firm to focus on what it believes are its core competences
Supplier handling costs can be reduced drastically since large number of component
suppliers are replaced by one system supplier
It fosters joint innovation and mutual learning
3 factors that determine the potential for succesful system sourcing (Gadde & Jellbo):
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The modularity of the overall system in which the purchased system has to fit in: How
intertwined is the purchased system with the overall product it has to fit in?
The capabilities of both the buying firm and the supplier: Can the buying firm effectively get
the new kind of higher level specification across to the supplier and can the supplier actually
take responsbility for the additional engineering of parts?
The degree of difficulty of separating development and production activities: can a system be
developed without much knowledge of technologies for producing parts of it?
2.3: Which type of ordering system should be used?
2 options to choose from:
1. Replenishment order (purchasing order): Automatically generated once the stock level drops
below a certain order level.
2. Replenishment order that is generated after a certain time interval has passed.
3. Purchasing processes evolve into different typical configurations
In practice more than 1 purchasing process is used. Many configurations appear. 3 of those
configurations are: New Task configuration – Modified rebuy – Straight Rebuy:
Purchasing must become Supply Management (Kraljic)
A company’s need for a supply strategy depends on two factors:
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The strategic importance of purchasing in terms of the value added by product line, % raw
materials in total costs and their impact on profitability etc.
The complexity of the supply market gauged by supply scarcity, pace of technology and/or
materials substitution, entry barriers, logistics cost or complexity, and monopoly or oligopoly
conditions.
To minimize supply vulnerability, a fourstage approach is used:
Phase 1: Classification: (Kraljic Matrix)
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Phase 2: Market Analysis:
suppliers against
The company weighs the bargaining power of its
its own strength as a customer.
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Suppliers’ capacity utilization: The risk of supply bottlenecks
Suppliers’ break-even stability
Uniqueness of suppliers’ product: If a product is unique, the profitability is less
Annual volume purchased and expected growth in demand: The main determinant of
the company’s overall bargaining power, economies of scale in purchasing often
yields a decisive competitive cost advantage.
o Past variations in capacity utilization of main production units
Potential costs in the event of nondelivery or inadequate delivery
Phase 3: Strategic Positioning:
(Purchasing Portfolio Matrix)
Purchasing Control (Boer&Telgen)
Purchasing: Anything resulting in an invoice
Spend Analysis: Nothing more than analyzing all purchases afterwards. It shows nothing on the
contents of the contracts or the purchases, it shows the volume of the purchases.
Accounts Payable: The starting point for a spend analysis. It’s a form of administration for all
payments. Only 4 data per invoice are essential in accounts payable:
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The amount paid
The supplier
The cost category
Cost center
Purchasing control is the activity which periodically carries out standard planning and control cycle.
An important advantage of purchasing control over a once-only spend analysis is the possibility to
introduce monitoring of contract compliance (using framework contracts for the entire company,
which can be systematically followed and analyzed).
Transportation summary (Chopra&Meindl Chapter 14 + Dictaat VRP 6-11 (excl. 8.2, 8.3.6, 9.2)
Chapter 14: Transportation in a Supply Chain
14.1: The role of transportation in a supply chain
Transportation refers to the movement of product from one location to another as it takes its way
from the beginning of the supply chain to the customer.
Shipper: The party that requires the movement of the product.
Carrier: The party that actually transports the product.
The effectiveness of transportation is not only determined by the shipper and the carrier, there are 2
other parties which have a significant impact on transportation: (1) The owners and operators of
infrastructure and (2) the bodies that set transportation policy worldwide.
14.2: Modes of transportation and their performance characteristics
Air
The air transportation mode’s cost are mostly determined before a flight takes off, therefore it is an
important objective of an airline to maximize the revenue generated per flight.
Air carriers offer a fast and expensive mode of transportation. Small, high-value items or timesensitive emergency transports have the best fit for air transport.
Package carriers
Package carriers are transportation companies which carry small packages (FedEx, UPS). Package
carriers use air, truck, and rail to transport time-critical smaller packages.
The major service package carriers provide is offering quick and reliable delivery. Package carriers
can’t compete with LTL or FTL carriers. Another added value of package carriers is that they provide
track-and-trace and some processing or assembly.
Given the small size of packages and lots of delivery points, consolidation of shipments is a key factor
to decrease costs and increasing utilization
Truck
The trucking transportation mode is more expensive than rail, but offers the advantage of door-todoor delivery and a shorter delivery time. Another advantage is that trucking transportation mode
does not need transfers between pickup and delivery of products.
There are 2 major segments: LTL and TL. TL operations have relatively low fixed costs. LTL operations
are priced to encourage shipment in small lots. LTL is best suited for shipments that are too large to
be mailed by a package carrier.
Rail
The most important task for the rail transportation mode is to keep locomotives and crews well
utilized, labor and fuel contribute to 60% of railroad expense.
Rail is an ideal transportation mode for carrying large, heavy, or high-density products over long
distances. Small, time-sensitive, short-distance or short lead time shipments rarely go by rail.
Water
A disadvantage of the water transportation mode is that it is limited to certain areas. Another
disadvantage is that water transportation is very slow and delays occur significantly.
Water transportation is best suited for carrying large loads at low cost. For the quantities shipped
and distances involved, water transport is by far the cheapest transportation mode.
Pipeline
Pipelines are primarily used for oil and gas transportation. Given the nature of the costs in setting up
a pipeline, pipelines are best suited when stable and large flows are required. Pipeline pricing usually
consists out of a fixed component and a variable component relating to the actual quantity
transported.
Intermodal (Combination of transportation modes)
Key issues in the intermodal industry involve the exchange of information to facilitate shipment
transfers between different modes because these transfers often involve considerable delays,
hurting delivery time performance.
14.3: Transportation infrastructure and policies
Transportation infrastructures often require government ownership or regulation because of their
inherently monopolistic nature. In absence of a monopoly, deregulation and market forces help to
create an effective industry structure.
If infrastructure is publicly owned, it is important to price usage to reflect the marginal impact on the
cost to society. If this is not done, overuse and congestion result because the cost borne by a user is
less than the marginal impact on total cost.
14.4: Design options for a transportation network
Direct shipment network to single destination (Supplier  Buyer Location)
The major advantage of a direct transportation network is the elimination of intermediate
warehouses and its simplicity of operation and coordination. Because each shipment goes directly to
the customer, the transportation time is short.
Direct Shipping with milk runs
A milk run is a route on which a truck delivers products from a single location to multiple retailers, or
vice versa, thus multiple retail locations to one buyer location.
Milk runs lower transportation costs by consolidating shipments to multiple locations on a single
truck. Milk runs make sense when the quantity destined for each location is small, and locations are
close to each other to combine.
All shipments via intermediate distribution center with storage (SuppliersDCBuyer Locations)
This option means that products are shipped to one location where it will be stored until needed,
then the product will be shipped to the buyer location.
Storing products at an intermediate location is justified if transportation economies require large
shipments on the inbound side or shipments on the outbound side cannot be coordinated. (Product
comes into the DC with large amounts and sent to buyer locations in smaller replenishment orders)
All shipments via intermediate transit point with cross-docking
Under this option, suppliers send their shipments to an intermediate transit point where they are
cross-docked and sent to buyer locations without storing them. With cross-docking, each inbound
truck contains products from suppliers for several buyer locations, whereas each outbound truck
contains products for a buyer location from several suppliers.
Cross-docking saves on handling costs because products don’t need to be moved into and out of
storage. Cross-docking is appropriate when economies of scale in transportation can be achieved on
both the inbound and outbound sides and both inbound and outbound shipments can be
coordinated.
Shipping via DC using milk runs
This option is the better alternative compared to ‘All Shipments via DC’ if lot sizes to be delivered to
each buyer are small. Milk runs reduce outbound transportation costs by consolidating small
shipments.
Tailored Network
The tailored network is a combination of all previous options that reduces the cost and improves
responsiveness of the supply chain. The goal is to use the appropriate option in each situation. The
complexity of managing a tailored network is high because many different shipping procedures are
used for each product and retail outlet.
14.5: Trade-offs in transportation design
All transportation decisions made by shippers need to take into account their impact on inventory
costs, facility and processing costs, the cost of coordinating operations, and the level of
responsiveness provided by the customers.
Transportation and inventory cost trade-off
Choice of transportation mode
Faster modes of transportation are preferred for products with high value-to-weight ratio for which
reducing inventorie is important, whereas cheaper modes are preferred for products with a small
value-to-weight ratio for which reducing transportation cost is important.
The choice of transportation mode should take into account cycle, safety, and in-transit inventory
costs besides the cost of transportation. If the purchase price changes when the transportation mode
changes, the purchase price must also be included.
Inventory aggregation
Inventory aggregation decisions must account for inventory and transportation costs. Inventory
aggregation decreases supply chain costs if the product has a high value-to-weight ratio, high
demand uncertainty, low transportation cost, and customer orders are large. If a product has a low
value-to-weight ratio, low demand uncertainty, large transportation cost, or small customer orders,
inventory aggregation may increase supply chain costs.
Trade-off between transportation cost and customer responsiveness
If a firm has high responsiveness and ships all orders within a day of receipt from the customer, it will
have small outbound shipments resulting in a high transportation cost. If it decreases its
responsiveness and aggregates orders over a longer time horizon before shipping them out, it will be
able to exploit economies of scale and incur a lower transportation cost because of larger shipments.
Temporal aggregation: The process of combining orders across time. Temporal aggregation
decreases a firm’s responsiveness because of shipping delay but also decreases transportation costs
because of economies of scale that result from larger shipments.
14.6: Tailored transportation
Tailored transportation is the use of different transportation networks and modes based on
customer and product characteristics. It allows a supply chain to achieve appropriate responsiveness
and low cost.
Tailored transportation by customer density and distance
Tailored transportation by size of customer
Firms must consider customer size and location when designing transportation networks. By
example, large customers can be supplied by FTL and small customers by LTL or milkruns. Also a
tailored milkrun in which large customers are visited more than smaller customers can be designed.
Tailored transportation by product demand and value
Dictaat VRP
Van tevoren wil ik iedereen aanraden sowieso het dictaat te lezen. Veel dingen zijn na een
visualisatie veel duidelijker dan ik in woorden kan beschrijven.
6. Inleiding
De doelstelling in een ritplanningsprobleem is het efficiënt en effectief beleveren van een groep
klanten met bekende vraag en locatie, vanaf een aantal depots met bekende locatie, door een vloot
transportmiddelen met bekende capaciteiten.
7. Overzicht
7.1: Routering en scheduling
Zuiver routeringsprobleem: Routeringsprobleem waarbij alleen rekening wordt gehouden met
geografische aspecten, de vraag en ligging van de klanten is belangrijk maar de tijd niet.
Routerings-schedulingsprobleem: Hier wordt wel rekening gehouden met de tijd, bijv. doordat een
klant slechts tussen een bepaald tijdsinterval mag/kan worden bezorgd.
Schedulingsprobleem: Wanneer tijdvensters zo strak zijn gedefinieerd dat iedere klant op een vast
tijdstip moet worden bezorgd en met een vaste bedieningsduur beleverd moet worden.
7.2: Vlootkarakteristieken
De vloot staat voor alle voertuigen die gebruikt worden om de klant te bedienen, de volgende
eigenschappen van een vloot spleen een belangrijke rol in het opzetten van een
ritplanningsprobleem:
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Omvang, vast/variabel
Voertuigcapaciteiten
Homogeniteit (Zijn alle voertuigen gelijk of niet?)
Bijzondere voertuigkarakteristieken, compartimentering
7.3: Depotkarakteristieken
De volgende depotkarakteristieken spelen een rol bij een ritplanningsprobleem:
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Het aantal depots
Toewijzing van voertuigen aan depots
Beperkingen op de depotcapaciteit
7.4: Klantenkarakteristieken
De volgende klantenkarakteristieken spelen een rol bij een ritplanningsprobleem:
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Aard van de handelingen (wegbrengen, ophalen of combinatie van)
Toestaan van gesplitste leveringen
Locatie van de vraag (vaste plaatsen of traject tussen A en B)
Aard van de vraag (deterministisch, vraag bekend / stochastisch, vraag onbekend)
7.5: Wegenkarakteristieken
Gericht/Ongericht wegennetwerk: In een gericht wegennetwerk wordt onderscheid gemaakt naar de
richting waarin een weg wordt afgelegd, bij een ongericht wegennetwerk niet. Denk hierbij aan
éénrichtingsverkeer, verkeersdrukte, verschillen in snelheid AB en BA.
Euclidisch netwerk: Ongericht netwerk waarbij de onderlinge afstanden tussen locaties precies de
Euclidische afstanden in het platte vlak voorstellen.
Een wegennetwerk moet voldoen aan de driehoeksongelijkheid: cik ≤ cij + cjk voor alle locaties i,j,k in
een netwerk.
7.6: Tijdrestricties
Wanneer er sprake is van tijdsvenster of volgorderelaties in een ritplanningsprobleem, spreken we
van een routerings-schedulingprobleem. Het probleem wordt niet langer gezien als een zuiver
routeringsprobleem.
De belangrijkste tijdsrestricties:
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Maximum op de rittijd
Tijdvensters
Volgorderelaties
Synchronisatie van voertuigen (omladen)
Planningshorizon
7.7: Routerestricties
Routerestricties betreft de maximale afstand die een voertuig af mag/kan leggen en het aantal ritten
per voertuig.
7.8: Kostenfactoren
 Variabele ritkosten (tarief per uur/km)
 Kosten per levering
 Vaste kosten per voertuig en/of depot
 Boetekosten voor het niet voldoen aan de vraag conform de condities
7.9: Optimalisatiecriteria
Per type vervoer kan de doelstelling anders liggen (veiligheid, comfort, minimalisering kosten etc)
7.10: Overige aspecten
Overige relevante aspecten zijn:
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Situatie-specifieke randvoorwaarden
Zachte randvoorwaarden
Tijdsafhankelijk en/of stochastische rijtijden
Vaste ritten
Dynamische planning
8. Het handelsreizigersprobleem
8.1 Probleembeschrijving
Handelsreizigersprobleem: Een handelsreiziger moet N steden afreizen. Elke stad moet hij precies 1
keer aandoen en aan het einde moet hij weer op de beginplaats zijn. Gegeven afstanden en kosten cij
tussen stad i en j, wat is de kortste route die de handelsreiziger kan afleggen?
Hamilton circuit / tour: Een route waarin alle steden met elkaar verbonden zijn.
8.3: Heuristische regels voor het handelsreizigersprobleem
Voor grote problemen zijn exacte oplossingen niet nodig, dan wordt er gebruikt gemaakt van
heuristieken. Deze heuristieken worden gebruikt om een bijna-optimale tour te vinden.
Heuristische regels worden opgedeeld in 2 groepen:
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Constructieregels: Beginnen met een lege route en voegen steeds nieuwe steden toe.
Verbeteringsregels: Beginnen met een toegelaten oplossingen.
Nearest neighbour:
Nearest insertion:
Farthest insertion:
2 opt:
3 opt:
Remaining chapters:
The remaining chapters are about showing how certain algorithms work. It is too hard to summarize
this on a pc, therefore I have made a guideline for each of the algorithms (in Dutch only). They are
shown below, I’ m afraid you have to zoom in to really see it:
Savingsalgoritme:
Assignment-Sweep
Route-first Cluster Second:
Multi-Depot Savingsalgoritme:
SCND Part (chopra&meindl chapter 4-5)
Chapter 4: Designing Distribution Networks and applications to online
sales
Distribution refers to the steps taken to move and store a product from the supplier stage to a
customer stage in the supply chain.
Logistics cost = Inventory cost + Transportation cost + facilities cost
Manufacturer Storage with Direct Shipping (Drop-shipping)
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Inventory is only held at the manufacturer
Retailer takes order from customer and places it at the manufacturer
Major benefit is centralized inventory at manufacturer who can aggregate demand across all
retailers, especially in case of slow-moving high value products
Long response time because of increased distance, not directly from retailer
Manufacturer Storage with in-transit merge network
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Inventory is kept at the manufacturer
In-transit merge combines pieces of the order coming from different manufacturers so that
the customer gets a single delivery  Lower transportation costs than drop-shipping
Major benefit is centralized inventories
Higher customer experience than drop-shipping because only a single delivery as to be
received
Especially suitable when you have a few factories with large product variety
Distributor Storage with Carrier Delivery
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Inventory is held by distributors in intermediate warehouses
Distribution centers are closer to customer than factories  faster response time
Inbound shipments to warehouse can be done by FTL
Outbound orders to customer is bundled in single shipment and done by carriers
Higher level of inventory due to loss of aggregation, so suitable fast-moving products with
predictable demand  lower product variety than manufacturer storage
Distributor storage with last-mile delivery
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Last mile delivery refers to the distributor delivering the product to the customer’s home
instead of using a carrier
More warehouses required to keep delivery time from distribution center to customer short.
Dominant design in the spare parts of automotive industry. AH with the delivery option
Higher inventory than distributor storage with carrier delivery
Very high transportation cost because of minimal scale of economies. Highest of all!
Very quick response time, same day or next day delivery
Less product variety than distributor storage with package delivery, larger than retail stores
Manufacturer or distributor storage with customer pick-up
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Inventory is held at both the manufacturer or distributor, customers place their order online
and then travel to pick-up points to get their product
Lower delivery cost and expand product variety
Less transportation cost
Response time also about same day - next day, depending on the items stored at pickup site
Retail Storage with customer pickup
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Customers walk into the store and buy products
Very high inventory cost, facilities cost and handling cost
Very low transportation cost
Lowest product availability (beperking door assortiment)
Very expensive to provide product availability
Impact of online sales on customer service:
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Response time to customer: Physical products take longer to fulfill than retail store. No delay
in information goods
Product variety: Easier to offer larger selection
Product availability: Aggregating inventory and better information on customer preferences
improves product availability
Customer experience: Improved access, customization and convenience
Returnability: Harder with online orders, proportion of returns likely to be much higher
Faster time to market and order visibility
Chapter 5: Network Design in the Supply Chain
5.1: The role of network design in het supply chain
Supply chain network design decisions include the assignment of facility role; location of
manufacturing- storage or transportation related facilities; and the allocation of capacity and
markets to each facility.
5.2: Factors influencing network design decisions:
 Logistics and facility costs, customer response time, strategic factors (Chapter 4)
 Technological factors and price
 Macroeconomic factors (taxes, exchange rates, freight and fuel costs, demand risk)
 Political factors, infrastructure factors
 Competitive factors: Positive externalities between firms, locating to split the market
Locating to split the market (assuming total demand = 1). If firm 1 locates at point a, and firm 2
locates at point 1-b, then demand of the 2 firms is given by (exam question last year):
d1 =
1−b−a
+a
2
,
d2 =
1+b−a
2
The companies maximize their market share if they move closer to each other and locate at a=1/2=b.
5.3: Framework for network design decisions
The goal when designing a supply chain network is to maximize the firm’s profits while satisfying
customer needs in terms of demand and responsiveness. Global network designs are made in 4
phases:
Hard infrastructure requirements: The availability of suppliers, transportation services,
communication, utilities, and warehousing facilities.
Soft infrastructure requirements: The availability of a skilled workforce, workforce turnover, and the
community receptivity to business and industry.
5.4: Models for facility location and capacity allocation
The goal when locating facilities and allocating capacity should to be to maximize the overall
profitability of the resulting supply chain network while providing customers with the appropriate
responsiveness.
The following information must be available when making design decisions:
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Location of supply markets and sources
Location of potential facility sites
Demand forecast by market
Facility, labor and material cost by site
Transportation costs by site and as a function of quantity
Sale price of product in different regions
Taxes and tariffs
Desired response time and other service factors.
(It is almost impossible to summarize the capacitated plant location model, the gravity location
model etc. therefore it is necessary to read the remainder of 5.4 yourself. I can remember a question
in which you had to find the perfect location, just calculate the average x and y coordinate).
5.5: Making network design decisions in practice
Managers should keep in mind the following things when design decision are made:
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Do not underestimate the life span of facilities (for example technology changes in the near
future can have a big impact)
Do not gloss over the cultural implications
Do not ignore quality-of-life issues (quality of life determines has an impact on performance)
Focus on tariffs and tax incentives when locating facilities