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83 Cards in this Set
- Front
- Back
Why is the study of waiting lines important in running a business? Especially in America? |
first come, first serve
if a company favors one person, everyone else gets offended because we think the company doesn't see us as equal |
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How do you make a customer happy? |
short lines |
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what is the cost of waiting to a customer? |
their time |
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what is the cost to the company for keeping lines short? |
money |
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waiting line goals |
find the proper balance between long lines/unhappy customers and idle staff/high cost |
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waiting line system diagram |
rectangle = business |
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balking is... |
the line alone scared them away before they actually enter the business |
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reneging is... |
they got in line, but decided to leave because the line was taking too long |
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finite pool (how many potential customers) |
few potential customers; every customer in the store significantly decreases the chance of another customer arriving
ex: retail store that sells jumbo jet airplanes |
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infinite pool (how many potential customers) |
many potential customers; odds barely affected by new arrivals
ex: mcDonalds |
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type of customers (degree of variability) |
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arrival rates (degree of variability) |
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single line |
first come, first served (FCFS); sense of fairness |
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multiple lines |
line jumping or jockeying |
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1st come, 1st served (priority discipline rules) |
served in order you arrive in; better system overall |
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earliest due date or shortest processing time (priority discipline rules) |
homework? |
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reservations or appointments possible (priority discipline rules) |
restaurants, homework |
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emergency situations (priority discipline rules) |
emergency rooms |
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preemptive discipline (priority discipline rules) |
special rules; VIP lines, frequent fliers |
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lambda |
mean arrival rate |
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mu |
mean service rate |
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always set up you rates this way |
numerator = customers, cars, reports
denominator = sec, min, hrs, days |
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rho |
= lambda / mu
percentage of time a server is busy |
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ns = |
average number of customers in the system |
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ts= |
average time spent in the system |
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nl= |
average length of queue |
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tl= |
average time spent in queue |
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n= |
customers |
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t= |
time |
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l= |
line or queue |
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s= |
system |
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Pn= |
(1-p)p^n
probability of EXACTLY n customers in the system
only works for single line single server model*
used in gambling |
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what is the probability of FEWER than 4 in the system? example |
p0+p1+p2+p3 |
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probability of 4 OR LESS in the system? |
P0+P1+p2+p3+p4 |
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probability of MORE THAN 4 in the system? |
1- (P0+P1+p2+p3+p4) |
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system measures illustration |
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probability of 4 OR MORE in the system |
1-(P0+P1+p2+p3) |
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2 are in line, but 3 are in the system |
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why are lines so long at DMV, post office, and amusement parks? |
there is no incentive to improve (government)
amusement parks have no competition |
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manager of taget salary starts at... |
125,000 |
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people pick grocery stores based on what department? |
produce - because everything else is fairly generic |
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what departments are almost always on the perimeter of grocery stores? |
liquor, produce, flowers, meat, milk, bakery, and deli |
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what are the 2 most profitable departments in a grocery store? |
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why are the milk (not including cheese and butter) and bakery departments usually in the corners of the store? |
because people get these items most often; exposes consumers to the whole store |
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facilitating goods are... |
items that need to be kept in inventory to maintain operations
ex: plates, utensils, etc |
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What is VMI? |
vendor managed inventory - inventory planning and replenishment system where supplier (vendor) accepts negotiated responsibilities that typically include monitoring and restocking |
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value to vendor and retailer of VMI |
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VMI challenges |
ex: if you tell all trucks to deliver between 6-10 and they all come at once, one may pull up out front and make a bad impression |
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upstream refers to... |
in the direction of the suppliers |
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downstream refers to... |
in the direction of the customer |
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back-end refers to... |
out of sight (to customers)
ex: why you don't have product on the shelf - workers too lazy etc |
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front-end refers to... |
visible to customers
ex: being rude to your customer |
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push system |
you buy a lot of materials, make a lot of computers, and send to the customer |
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push system advantages |
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push system cons |
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pull system |
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pull system advantages |
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pull system cons |
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2 outcomes possible:
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Should you use a push or pull system? |
the market should dictate your strategy
if it wants high customization, use pull
if the market is static, nothing changing, you should use push
neither is good unless you are using it in the right manner |
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old school vs new school philosophies |
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Lean manufacturing philosophy |
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primary goals of Lean manufacturing: JIT philosophy |
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managing lean manufacturing for the long-run |
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why is lean manufacturing required in Japan? |
because real estate costs are so high, they need to have a small EOQ for it to make sense |
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recap of supply chain basics |
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focus on people (recap of supply chain basics) |
good SC decisions positively impact customers, employees, and investors |
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competitive priorities (recap of supply chain basics) |
good SCs deliver the right mix of cost, quality, speed, and flexibility to their target market |
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measuring success (recap of supply chain basics) |
the best SCs are effective (great products), efficient (minimal resources/waste), and adaptable (ready for change; constantly evolving) |
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maximize value (recap of supply chain basics) |
provide customers the best possible product and service bundle at the lowest possible cost and in the most convenient way |
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productivity (recap of supply chain basics) |
maximize a company's high quality output using the fewest resources possible |
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8 SC processes |
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shrinkage formula |
order size required = (actual demand) / (proportion of acceptable product per order)
(300) / (100% - 2%)
always round up; from retailer to supplier |
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square root rule - risk pooling |
inventory future = inventory present [(sqrt WH future) / sqrt WH present)]
ex: going from 4 to 2 warehouses:
inv future = 6000 [(sqrt 2) / (sqrt 4)] |
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Integration is... |
the bringing together of groups that were separated in the hopes of seeing improvements |
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the bullwhip effect is... |
a SC phenomenon where fairly stable demand results in a proliferation in the amount of inventory that is carried as one travels upstream in the SC |
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causes of the bullwhip effect |
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order batching (causes of the bullwhip effect) |
when companies place large and infrequent orders from their suppliers; typically done to take advantage of quantity discounts and economies of scale in purchasing and delivery; creates communication gaps (uncertainty) |
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forward buying (causes of the bullwhip effect) |
is the result of suppliers offering sales; buyers want to take advantage of low prices, but aren't buying based on demand, but rather on price; causes true demand to be unknown by suppliers |
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shortage gaming (causes of the bullwhip effect) |
often caused by rationing; buyers often place larger orders than required bc they are afraid of being rationed |
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controlling the bullwhip effect (2 ways) |
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keys to lean manufacturing |
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poka-yoke (keys to lean manufacturing) |
mistake-proofing
5 wires connecting to different devices; solution is to make each wire have a different connector to the specific device |