LSCM 3960 ch 10
reliability
is a critical issue. Many companies feel that transit time reliability is more important than speed as it impacts their ability to plan supply chain activities. Reliability refers to the consistency of the transit time provided by a transportation mode. It is easier to forecast inventory needs, schedule production, and determine safety stock levels if it is known with some certainty when goods will arrive. Reliability is measured by the statistical variation in transit time. Modal reliability is impacted by a variety of factors including equipment and labor availability, weather, traffic congestion, freight-handling requirements, number of terminal stops involved, and other factors. Internationally, reliability is impacted by distance, port congestion issues, security requirements, and border crossings, especially when the two countries do not have a proactive trade agreement. • Reliability advantage: Motor carriers and air carriers, as they are the most reliable (variability relevant to average transit time). • Reliability disadvantage: Water carriers and rail carriers. With capacity and congestion challenges, they have become less consistent. As a result, some customers have reduced their use of these modes when possible.
There are five primary modes of transportation and an intermodal transportation model
motor carriers, railroads, air carriers, water, pipeline
Railroads fall into a group called
natural monopolies
Discuss the elements of carrier selection, and how it differs from mode selection.
Carrier selection is a specialized purchasing decision that typically will be made by a logistics, transportation, or traffic manager who has expertise and experience in the purchase of transportation services. After the modal decision has been made, attention turns to selecting the individual transportation service providers within the mode. Like the modal decision, carrier selection is based on a variety of shipment criteria and carrier capabilities: transit time average and reliability, equipment availability and capacity, geographic coverage, product protection, and freight rates. A major difference between modal and carrier selection is the number of options. Modal selection involves six primary options, but the carrier selection may involve fewer or many more alternatives. In the case of rail transportation, many markets are only served by a single carrier and the choice is limited. At the other extreme is truckload transportation where dozens of carriers serve a particular market. Another difference is the frequency of the decision. Carrier selection requires more active and frequent engagement of the transportation buyer than does the more long range modal selection decision. This engagement does not focus on choosing a new carrier for each freight move; it focuses more on the transportation buyer remaining vigilant and managing the performance of chosen carriers. It is critical to monitor each carrier's service level and freight rates on an ongoing basis. Should carrier performance deteriorate, it may be necessary to select new service providers. The type of service provided within a mode impacts carrier selection. Most carriers have their roots in one of two types of service—direct service or indirect service—between which customers must choose. Within a mode, most carriers have the capabilities to provide a similar level of service, but these service levels can and do vary greatly from one transportation company to another. Also, since the cost structures are essentially the same for carriers in a given mode, their rates tend to be aligned for a given movement. Given this similarity, transportation rates tend not to be the most important criterion in carrier selection. Service performance is the key determinant for this decision. Carrier selection research suggests that reliability of on-time delivery and on-time pickup, technical capabilities, carrier response to emergencies, information sharing, freight damage experience, carrier financial stability, and total transit time are among the most important criteria to transportation service buyers. Carrier selection strategy commonly focuses on concentrating the transportation buy with a limited number of carriers. Using a small group of carriers helps the organization leverage its purchasing dollars for lower overall rates, build relationships with service providers who gain a better understanding of freight flows and requirements over time, and effectively monitor performance of the carrier base. In many cases, the core carriers become an indispensable extension of the organization's transportation management team; they are able to manage freight flows across the supply chain with limited direction or oversight. The ability to rely on the transportation expertise of trusted core carriers also allows the organization to focus its attention on other supply chain issues
Transportation efficiency promotes __________ in the supply chain.
Competition
Challenges for the trucking industry include
competition
Air carriers were historically looked upon as
emergency only carriers
15. Some companies like PepsiCo have chosen to move freight on company operated equipment, despite the fact that these private fleets cost more than for-hire carriers. t/f
false
A carrier is never excused from a claim. t.f
false
CBP is now enforcing the "48 Hour Rule". t/f
false
Following the trend in deregulation of most transportation modes, freight rate negotiations are being decentralized. t/f
false
Given the availability of information, transportation buying has become comparatively easy. t/f
false
Intermodal growth has been flat.t/f
false
KPI is another term for a shipping document. t/f
false
The main strategy behind routing guides is to maintain very tight control of transportation costs. t/f
false
Which management area in an organization does not normally have transportation responsibility?
manufactoring
Which of these is not a freight document
routing guide
5. Motor carrier cost is highly variable. t/f
true
A bill of lading can be either straight or order. t/f
true
Trade imbalances affect
water carriers
motor carriers (primary mode of transportation)
Motor carriage is the most widely used mode of transportation in the domestic supply chain, ranging from the smallest delivery van to the largest tractor-trailer combination. The sophisticated U.S. highway network permits trucks to reach all points of the country. This accessibility combined with the industry's excellent service capabilities, has made trucking the mode of choice for high-value, time-sensitive goods. The trucking industry is highly competitive and made up of 502,000 private, for hire, and other U.S. interstate motor carriers. There are no significant cost economies of scale that make it impossible for small carriers to compete. Most expenses are incurred as the result of moving freight; thus, trucking is a high-variable-cost, low-fixed-cost business. Much of the freight moved by the trucking industry is regional in nature, moving within a 500-mile radius of the origin. The trucking industry is comprised of for-hire and private fleet operations. Private fleets primarily transport freight that is owned by the organization that is operating the trucks. Motor carriers face daunting challenges in the future—rising costs, labor issues, and competition. Trucking companies are able to pass along rising fuel and insurance costs during economic expansions, but cannot always do so if capacity exceeds demand. A shortage of truck drivers will only become more serious as current drivers retire. Finally, competition will remain fierce, with customers expecting near-perfect performance.
Air carriers (primary mode of transportation)
The advent of e-commerce, the growth of global supply chains, and initiatives to reduce inventory and order cycle time have contributed to a sustained increase in demand for air transportation. While air cargo transportation remains a small and specialized mode in terms of tonnage, U.S. spending was $33 billion in 2010. Worldwide, air cargo industry revenues are approaching $594 billion, and freight traffic is projected to grow at an annual rate of 6.1 percent over the next 20 years. The FAA activity report identifies 88 carriers that are engaged in air cargo, 22 of which are considered major carriers. The air carrier cost structure consists of high variable costs in proportion to fixed costs, somewhat akin to the motor carrier cost structure. Like motor and water carriers, air carriers do not invest heavily in facility infrastructure or byways. The government builds terminals and provides traffic control of the airways. Air carriers pay variable lease payments and landing fees for their use. Equipment costs, though quite high, are still a small part of the total cost. Air transportation is used to ship small quantities of high-value, low-weight, semi-finished, and finished goods. The air cargo industry faces numerous obstacles to profitable growth, including cost issues, competition, and security challenges. The rising cost of fuel directly impacts the success of the industry. The growth of next-day trucking services is putting pressure on the domestic air cargo industry. Air carriers may find it difficult to pass along increased costs in the face of this growing competition. Finally, the industry is under pressure from costly security mandates, which are estimated to have an annual impact of more than $4 billion on the industry.
cost
The cost of transportation is an important consideration in the modal selection decision, especially when a low-value commodity needs to be moved. Transportation costs include the rate for moving freight from origin to destination plus any accessorial and terminal fees for additional services provided. Examples of these additional costs include inside delivery to a retailer located inside a mall, packing freight in crates for international delivery, or setting up a delivery of furniture in a residential location. A number of factors are taken into consideration when freight rates are developed, including weight of the shipment, distance from origin to destination, nature and value of the product, and the speed required. • Cost advantage: The cost of transportation service varies greatly between and within the modes. In general, pipeline, water, and rail service are low cost transportation methods. The tradeoff, of course, is slow speed, which forces a company to hold a greater level of inventory to meet demand during these longer transit times. • Cost disadvantage: Motor carriage and air transportation are high-cost modes compared to the others. On average, motor carriage is about 10 times more expensive than rail, and air service is more than twice the cost of motor carriage. Given the varying capabilities and cost of each transportation mode, it is obvious that modal selection is not a quick and easy process.
What are the three types of freight documentation? Discuss how each is used
bill of lading, freight bill, freight claim forms
Desirability refers to
characteristics that influence modal selection
accessibility
determines whether a particular mode can physically perform the transport service required. Accessibility considers the mode's ability to reach origin and destination facilities and provide service over the specified route in question. The geographic limits of a mode's infrastructure or network and the operating scope that governmental regulatory agencies authorize also affect accessibility. Accessibility problems often eliminate a mode from consideration during the selection process. • Accessibility advantage: Given the road networks in most countries, motor carriage is more accessible to sellers and buyers than any other mode for domestic transportation. • Accessibility disadvantage: Air, rail, and water. All face accessibility limitations due to infrastructure issues. Still, all three modes serve virtually every major market thanks to intermodalism.
Procuring inexpensive transportation is the major goal of supply chain managers. t/f
false
The railroads have not shared in the growth in transportation and so do not have any capacity issues. t/f
false
The responsibly for transportation management is typically not assigned to any one management discipline in an organization. t/f
false
Security legislation
has caused expense issues for carriers.
freight claims form
is a document that the transportation buyer files with the carrier to recoup monetary losses resulting from the carrier's failure to properly protect the freight. The shipper must file in writing freight claims with the carrier within a timeframe specified in the contract. Freight claims can be filed for visible damage or shortages that are detected when the product is received and inspected, for concealed losses that are not discovered until packages are opened, or for financial losses due to unreasonable delays. Carrier liability is limited if the shipper elected to send the goods under a released value in exchange for lower freight rates. Carriers are not liable for freight claims if the damage is attributable to some uncontrollable factor, such as a natural disaster, military attack, extreme fragility, etc
bill of lading
is probably the single most important transportation document. It originates the shipment, provides all the information the carrier needs to accomplish the move, stipulates the transportation contract terms including the scope of the carrier's liability for loss and damage, acts as a receipt for the goods the shipper tenders to the carrier, and in some cases shows certificate of title to the goods. The bill of lading is created by the shipper of the goods and is either negotiable or nonnegotiable. A straight bill of lading is nonnegotiable, and the carrier must deliver the goods only to the specific receiving organization and destination in return for freight charge payment. An order bill of lading is negotiable and serves as a title to the goods listed on the document. The owner of the goods has the right to transfer title to the goods to another party and reroute the shipment to a location other than the one listed on the bill of lading. Bills of lading also differ by type of move and whether the transportation is domestic or international.
A key requirement for service quality monitoring is information. t/f
true
All modes of transportation provide the same basic service. t/f
true
Nonintegrated air carriers do not supply door-to-door service. t/f
true
Outsourcing transportation is a "buy" decision. t/f
true
Pipeline costs are predominantly fixed. t/f
true
Product value is an important factor in modal selection. t/f
true
Railroad's length of haul is longer than that of motor carriers. t/f
true
Railroads have accessibility limitations. t/f
true
The growth of outsourcing has created transportation challenges. t/f
true
Terms of sale establish
when ownership and title of the goods passes from seller to buyer.
Which is not a mode of transportation?
3PL
What is modal selection? What are the key determinants in choosing a mode?
A critical transportation management issue is modal selection; it affects how quickly and efficiently products will flow across portions of the supply chain. If an organization has determined that controlling the transportation process and using external service providers (for-hire carriers or 3PLs) are in its best interest, it must then determine which mode(s) of transportation to use. Choosing among the six modal options is a function of three factors—modal capabilities, product characteristics, and modal freight pricing. All modes provide the same basic service of moving freight from point to point in the supply chain. However, the modes serve different customer requirements and goods in terms of value, tonnage, and ton-miles. The reason for the different uses is that each mode has unique attributes and capabilities that impact its ability to serve specific customer requirements. Numerous studies have been conducted over the years to identify the most important performance capabilities in modal selection. These studies commonly identify accessibility, transit time, reliability, and product safety as the key determinants in choosing a mode. Of course, cost is another critical consideration in modal selection. key to choosing them: accessibility, transit time, reliability, product safety, and cost
Define FOB terms and discuss the various areas they cover.
Free-on-board (FOB) terms of sale specify when the ownership and title of the goods pass from a seller to a buyer in a domestic transaction. Wise selection of FOB terms determines control over mode and carrier selection, transportation rate negotiation, and other key decisions. Another important aspect of terms of sale is the determination of in-transit freight accountability. FOB terms determine where the buyer's responsibilities begin and where the seller's responsibilities end. If the terms are FOB origin, title (ownership) to the goods changes hands at the origin—usually the shipping point or seller's distribution center loading dock. From that point on, the goods belong to the buyer, and any loss or damage is the responsibility of the buyer. If the terms are FOB destination, the title transfers at the destination—typically the buyer's unloading dock. The seller has total responsibility for the goods until they are delivered to the buyer. A related issue is the responsibility for carrier payment. In general the seller pays the carrier for the transportation service cost under FOB destination terms, while the buyer pays the carrier under FOB origin terms. However, exceptions to these guidelines do occur. The option for Freight Prepaid or Freight Collect should be specified with the FOB terms. In cases where the seller has more clout with carriers, it is wise to have the seller negotiate transportation rates under the Freight Prepaid option. Freight Collect is typically used when the buyer has more power with carriers.
Intermodal Transportation
Intermodal transportation service refers to the use of two or more carriers of different modes in the origin-to-destination movement of freight. The primary benefits of intermodalism include the greater accessibility that can be created by linking the individual modes; the overall cost efficiency that can be achieved without sacrificing service quality or accessibility; and the fact that intermodal transportation facilitates global trade. There is strong evidence that intermodal transportation has grown in importance and volume. The number of containers flowing around the world from U.S. ports has increased from 15.5 million TEUs in 1990 to 37.2 million TEUs in 2009. Experts predict that this trend will continue as the global economy recovers. Domestic flows of intermodal freight have also risen over the same 20-year period. For example, the U.S. rail system moved 8.2 million containers and 1.6 million trailers in 2009. Much of this intermodal growth can be attributed to the development of standardized containers that are compatible with multiple modes. Other factors that have contributed to the growth of intermodal transportation include better information systems to track freight as it moves through the supply chain, development of intermodal terminals to facilitate efficient freight transfers between modes, and new generations of ocean vessels, railcars, and truck trailers that handle greater quantities of intermodal freight with greater ease. A recurring issue in the intermodal transportation market is congestion. Transfer points are not as flexible and can get clogged with freight. Equipment shortages, transfer facility congestion, and labor issues create delivery delays and supply chain disruptions. Infrastructure investment, equipment purchases, and operator hiring will be needed to prepare for the anticipated growth of intermodal transportation. (Pages
What are Incoterms, and what terms of sale decisions do they help to clarify?
International terms of sale are covered by International Commercial Terms (Incoterms). International transactions often present greater challenges, and parties to the transaction must understand how these terms of sale can impact transportation decision making. Even a relatively straightforward international transaction involves long distances, multiple modes of transportation and logistics intermediaries, duties and tariffs, government inspections, and significant opportunity for damage or delay. Thus, transportation managers must be extremely concerned about when and where the title to the goods will change hands. Incoterms facilitate efficient freight flows between countries. As described by the International Chamber of Commerce, Incoterms are international rules that are accepted by governments, legal authorities, and practitioners worldwide for the interpretation of the most commonly used terms in international trade. They address matters relating to the rights and obligations of the parties to the contract of sale with respect to the delivery of goods sold. These terms of sale decisions help to clarify the following questions: • Who will be responsible for control and care of the goods while in transit? • Who will be responsible for carrier selection, transfers, and related product "flow" issues? • Who will bear various costs - freight, insurance, taxes, duties, and forwarding fees? • Who will handle documentation, problem resolution, and other related issues? The most recent update, known as Incoterms 2010, is an effort to simplify these trade terms. The number of Incoterms options has been reduced from 13 to 11, seven of which apply to all modes of transportation and four of which apply only to water transportation. Among other changes, Incoterms 2010 have been clarified so that they can apply to both international and domestic freight. Taking control of freight through Incoterms allows organizations to leverage their purchasing power with specific carriers to achieve lower rates, coordinate inbound and outbound flows, and consolidate freight to achieve greater efficiencies. Other potential benefits include the ability to manage risk, achieve greater freight visibility, and ensure available equipment capacity
pipeline (primary mode of transportation)
Pipelines handle 5.2 percent of U.S. freight tonnage. This is a unique mode of transportation as the equipment is fixed in place and the product moves through it in high volume. Pipelines effectively protect the product from contamination and also provide a warehousing function. Pipelines provide the most economical form of transportation with the lowest cost per ton of any mode. The U.S. has the largest network of energy pipelines of any nation in the world. Pipeline costs are predominantly fixed. Pipeline operators must build their own right-of-way, which is a rather expensive proposition. Variable costs in the industry are very low as little labor is required to operate the pipelines and limited fuel is needed to run pumps. The construction of a pipeline becomes cost effective when product flows continuously, allowing the fixed costs to be spread over a high volume of goods. The vast majority of products moved by pipeline are liquids and gases, the economically feasible products to flow via this mode. The pipeline industry is comprised of for-hire and private carriers that maintain their own infrastructures. For-hire carriers of liquid products can move different products through their system at the same time, separated by a batching plug that maintains the integrity of individual products. Private carriers include petroleum and natural gas companies that use pipelines to move product to and from their refineries, processing plants, and storage facilities. The ongoing issues for the pipeline industry are safety and security. Compared to other modes, pipelines have enviable safety and environmental records with spills amounting to only one gallon per million barrel-miles. However, vigilance is critical because pipeline accidents can quickly become catastrophic events. Pipeline operators must also be cognizant of security risks and should maintain contingency plans to deal with hurricanes or terrorist attacks.
railroads (primary mode of transportation)
Railroads transport more than 1.9 billion tons of freight annually despite a lack of direct accessibility to all parts of the supply chain. Rail service is perceived as being a slow, inflexible, and inconsistent mode. The industry is dominated by seven Class I railroads (revenues in excess of $379 million). None of these major rail carriers services the entire country by itself; they work together via interline agreements to provide coast-to-coast rail service. This mode requires a large investment in terminals, equipment, and trackage to begin operation; the accompanying huge capacity allows railroads to be a decreasing cost industry. As output (ton-miles) increases, the average per-unit production cost decreases. Rail transportation is primarily used for the long-distance movement of low value raw materials and manufactured products but they also handle some high-value goods, primarily automobiles and intermodal containers filled with imported finished goods. In fact, intermodal volume is rising faster on a percentage basis than traditional rail freight. The rail industry faces a number of challenges moving forward. Capacity is an ongoing concern. With the track infrastructure remaining largely unchanged, additional freight, crews, and equipment cannot dramatically impact system delays.
product safety
Safety is critical to the achievement of customer service, cost control, and supply chain effectiveness. From a safety standpoint, goods must arrive at the destination in the same condition they were in when tendered for shipment at the origin. Proper precautions must be taken to protect freight from loss due to external theft, internal pilferage, and misplacement, as well as damage due to poor freight-handling techniques, poor ride quality, and accidents. Safety is often pursued through substantial protective packing. • Safety advantage: Air transportation and motor carriage have the best reputations for product security. Their equipment provides excellent ride quality and protection from the elements. Faster transit times also reduce the opportunity for theft and other mishaps. • Safety disadvantage: Rail and water face significant challenges to maintaining product integrity. Goods moving via rail encounter a great deal of vibration, swaying, and jarring. Water transportation often exposes goods to the elements, excessive movement, and rough handling during the loading and unloading processes.
Define and discuss Transportation Management Systems (TMS)
Software tools related to the movement of goods across the supply chain are lumped together in a general category called transportation management systems (TMS). TMS is defined as information technologies used to plan, optimize, and execute transportation operations. This simple definition captures the essence of TMS, presenting it as a melting pot of applications used to assist managers in nearly every aspect of transportation from basic load configuration to complex transportation network optimization. The planning capabilities of TMS assist transportation buyers and managers with the key pre-shipment decisions discussed earlier. These individuals cannot adequately evaluate the thousands of potential lane/mode/carrier/service/price combinations in their supply chains without technological help. TMS tools allow organizations to consider a vast array of transportation options in a matter of minutes versus hours or days of manual design activity. In addition, freight planning tools can be linked to order management systems, warehouse management systems, and supply chain planning tools to gain timelier, more comprehensive information. With this knowledge, better supply chain decisions and tradeoffs can be made. • Critical TMS planning applications include routing and scheduling, and load planning. TMS execution tools help transportation managers streamline some of their shipment activities. With multiple shipments needing delivery each day, manual processes are susceptible to errors, missed deadlines, and customer service failures. Various TMS capabilities automate repetitive activities to reduce labor costs and accuracy problems. For example, standardized templates can be used to ensure that complete and accurate shipment data are provided in transportation documents. Other tools post detailed shipment information to a shared network or a Web site to promote shipment visibility and provide greater freight control. • Three of the key execution tools include load tendering, status tracking, and appointment scheduling. TMS analytical tools provide organizations with the ability to make postshipment evaluations of carrier performance, customer service, and network cost. The data required for analysis can be spread across the entire supply chain in a variety of documents and information systems. It is critical to collect these data in a timely fashion so that the KPIs can be measured, performance assessed and benchmarked, and corrective action taken. TMS help organizations assemble and make sense of the vast array of transportation data that are generated by freight movement. • Two useful analytical applications are performance reporting and scorecarding, and freight bill auditing
Transportation plays a key role in supply chain design, strategy development, and total cost management in three areas.
Transportation service availability, capacity, and costs influence decisions regarding the number and location of supply chain facilities. For example, many organizations attempt to avoid locating distribution facilities in the state of Florida due to transportation costs. Transportation capabilities must align with the company's goals. In its 2009 annual report, Amazon.com states that it seeks to be Earth's most customer-centric company and strives to provide easy-to-use functionality, fast and reliable fulfillment, and timely customer service. To hit the targets, Amazon.com needs to partner with carriers that deliver customer orders consistently and quickly, provide shipment visibility, and charge reasonable shipping rates. Intentional tradeoffs should be made between transportation and related activities (e.g., procurement, production, and inventory management) to optimize supply chain efficiency. For example, retailers can hold lower safety stock levels if the cost of more frequent, faster deliveries does not exceed the inventory carrying cost savings. Similarly, manufacturers can employ lean production strategies if lot sizes can be minimized without creating excessive transportation costs.
water (primary mode of transportation)
Water transportation is a major facilitator of international trade. $115 billion worth of freight and 4.7 percent of the total ton-miles annually is moved via water transportation. Globally, water carriers dominate all other modes, garnering approximately half of the international freight revenue and handling nearly all tonnage. Although very slow and limited by the natural infrastructure, domestic water carriers offer tremendous capacity per vessel, efficient fuel consumption, and low cost. The economics of water transportation is similar to that of airlines as these carriers require no investment for the right-of-way and government entities known as port authorities provide unloading and loading services, storage areas, and freight transfer facilities. The water carriers pay user fees for these port services only when used. Large oceangoing ships require significant capital investments, but cost is spread over a large volume of freight transported during the lengthy life span of most ships. The domestic carriers compete vigorously with railroads for long-distance movement of low-value, high-density, bulk cargoes that mechanical devices can easily load and unload. However, water carriers handle a wider variety of goods. Every conceivable type of cargo is transported via international water carrier, from low-value commodities to imported automobiles. The major challenges faced by carriers in international water transportation relate to capacity, trade imbalances, environmental concerns, and security. Capacity shortages can be a problem when the global economy is growing, but the problem shifted to excess capacity during the global recession. Also, the imbalance of international trade between export-dominant Asian countries and import-dominant North America can create equipment availability problems at the origin and port congestion problems at the destination. The industry must also work to reduce carbon dioxide emissions as ships burning low-grade fuel account for 4.5 percent of all global emissions of this greenhouse gas. Security is a multifaceted challenge that must be addressed. Piracy is a growing problem.
Economic deregulation sparked competition among carriers in several areas. Which of these is not an area of competition?
accessibility
The distances in today's global supply chains produce
all of these -higher cost. -longer transit times. -more disruptions.
freight bill
is the carrier's invoice for the fees the carrier charges to move a given shipment. The freight bill lists the shipment, origin and destination, consignee, items, total weight, and total charges. The freight bill differs from the bill of lading in that the freight bill sets forth the charges applicable to the shipment while the bill of lading sets forth the terms of the shipment and is a document of title.
transit time
is the total elapsed time that it takes to move goods from the point of origin to the destination (i.e., door to door). This includes the time required for pickup activities, terminal handling, linehaul movement, and customer delivery. Companies typically monitor average transit time for their service providers. Transit time is impacted by the speed of the mode and the ability of the mode to handle pickup and delivery responsibilities. • Transit time advantage: Air transportation is very fast for the linehaul move but loses some velocity as pickup and delivery activities must be handled by truck. Motor carriage is also relatively fast because it can provide more direct movement from origin to destination far more often than any other mode. • Transit time disadvantage: Rail, water, and pipeline are extremely slow with average transit speeds of 22 miles per hour, 5-9 miles per hour, and 3-4 miles per hour, respectively.
The main strategy behind routing guides is to
promote supply chain excellence