BUS-P 370 Module 4: Flow Time and Management I and II

The ______________ is based on the assumptions that project activity times can be estimated accurately and that they do not vary.

critical path method

The _____________ of activities in a project is the sequence of activities that form the longest chain in terms of their time to complete.

critical path

t/f: if any one of the activities in the critical path is delayed, then the entire project is delayed.

True

The ___________________ of an activity is the activities that need to be completed immediately before another activity.

immediate predecessor

____________ in an activity refers to the leeway in when an activity can start and finish.

Slack time

The difference between the late start time and the early start time is the ____________.

slack time.

Do you start from the beginning or end of the network when determining late start times?

The end

An _______________ lists all activities by their earliest start time.

early start schedule

Activities not on the critical path will have ______________ between the completion of each activity and the start of the next activity.

slack time

The _______________ lists the activities to start as late as possible without delaying the completion date of the project.

late start schedule

____________________ are extensions of the basic critical path method in an attempt to develop a minimum-cost schedule for an entire project and to control expenditures during the project.

Time-cost models

_____________ in a minimum-cost schedule refers to the compression or shortening of the time to complete the project.

Crashing

The costs associated with expediting activities are termed ___________________ and add to the project direct costs.

activity direct costs

The costs associated with sustaining the project are termed ________________, such as overhead, facilities, and resource opportunity costs.

project indirect costs

What are the four categories of projects?

Product change, process change, research and development, and alliances and partnerships

A ____________ project is where the team works full-time on a project.

pure

A ______________ project is where team members stay in their functional groups and work on many different projects

functional

A ____________ project blends the pure project and functional project structures

matrix

Crashing creates a shorter project that costs ____________.

more

T/F: The manager must weigh the added cost of providing more rapid service (more traffic lanes, additional landing strips, more checkout stands) against the inherent cost of waiting.

True

T/F: Frequently, the cost trade-off decision is straightforward on the phone for technical help.

True

Segmenting the customers, training your servers to be friendly, informing your customers of what to expect, diverting the customers' attention, and encouraging customers to come during slack periods are all methods of ________________ in the banking industry.

managing queues

The ______________ consists of three major components: (1) the source population and the way customers arrive, (2) the servicing system, and (3) the condition of the customers exiting the system.

queuing system

______________ at the service system may be drawn from finite or infinite populations.

Arrivals

A ____________ population refers to the limited-size customer pool that will use the service, and at times, form a line.

finite

An _____________ population is large enough in relation to the service system that the population size is not affected by subtractions or additions to the population.

infinite

An ____________ rate is the number of units per period.

arrival

A ____________ arrival distribution is periodic, with the same time between each successive arrival.

constant

Factors to consider with ______________ include line length, number of lines, and queue discipline.

waiting lines

_____________ is the capacity of the service in units per time period.

Service rate

When the arrival process is random during some time period t, which distribution should be used?

Poisson

What factors impact flow time?

critical path, variability, WIP limit, batch size, and setup times

______________ can enter a system through many ways, primarily through (1) the interarrival time of successive jobs to the system, (2) the service time of processing steps within the system

Does slowness accumulate in an interdependent system with variability?

yes

Does fastness accumulate in an interdependant system with variability?

no

Does reducing variability reduce system flow times?

yes

Will you always improve flow time when you add capacity to a bottleneck?

No

To ensure you are reducing flow time, you should focus on the ___________ of a process flow and variability in the system.

critical path

CV=

standard deviation/mean

A CV less than 1 is _____________ reliable processing due to things like reservation systems or standard operating procedures.

more

A CV more than 1 is __________ reliable behavior such as "clumpy" arrivals or unpredictable processing times.

less

Does a CV of 2 have more or less variation than a

Is a CV=2 more or less reliable than CV=1?

Less (because more variation)

What is it called when CV=1?

Markovian

What is it called when CV=2

general

What is it called when CV=0.5?

General

What is it called when CV=0?

deterministic

Does a CV=0 have any variation?

No

When managing a line, a manager must consider the trade-off between___________________________.

the cost of providing more rapid service and the cost of waiting

The queuing system consists essentially of three major components. What are they? Check all that apply.

1.) The condition of the customers on exit

2.) The servicing system

3.) The source population and how it arrives

When the arrival process is random during some time period T, what distribution should be used?

Poisson

When using the exponential distribution as an approximation of the service times, we will refer to μ as what?

Average number of units that can be served per time period

Early finish =

early start + duration

Does crashing create a shorter or longer project?

shorter

Does crashing increase or decrease the costs of a project?

increases

What type of arrivals occur when customers arrive with exactly the same time between successive arrivals?

constant

When customers arrive at a service facility in a purely random fashion, it is expected that it follows which distribution?

exponential

Which Greek symbol is used to represent the average service time in an infinite queuing model?

1/μ

________________ refers to the compression or shortening of the time to complete the project.

crashing

Which Greek symbol is used to represent the service rate in an infinite queuing model?

μ

A constant service time is generally limited to _______________ operations.

machine-controlled

Slack time =

late start - early finish

Which Greek symbol is used to represent the average time between arrivals in an infinite queuing model?

1/λ

Which of the following terms describes the number of customers that can be handled during a given time period?

service rate

Is the distraction technique selected a major component of the queuing system?

no

Can a project have multiple critical paths?

yes

How many elements must a population have before it can be defined as infinite?

it depends

Any activity on the critical path will have a slack time of __________.

0

Do activities not on the critical path have slack time?

Yes

__________________ is the practice of producing or processing multiple units of an item together as a group, rather than producing one at a time.

Batching (lot sizing)

Batching refers to the decision of ______________ to produce (or order) at one time.

how many units

What is the first stage of the little field game?

Board stuffing

Jobs can get processed __________ with smaller lot sizes.

faster

______________ is the time required to prepare a machine for the process or production of the next job.

Setup time

Total processing time =

setup time + (pure processing time * # items in a batch)

When pooling several servers (processors), while keeping everything else (e.g., arrival rate, processing times, variability in arrivals and service times) the same, what happens to the average utilization?

nothing ( the average utilization stays the same)

Does increasing capacity at the bottleneck change throughput?

Yes, it increases throughput

Does increasing capacity at the bottleneck change flowtime?

Yes, it decreases flowtime (less waiting upstream since the bottleneck clears faster)

Does increasing capacity at the bottleneck impact utilization?

Yes, it decreases utilization (since the bottleneck has more capacity relative to demand)

Utilization=

Arrival Rate/Service Rate

Does increasing demand (arrival rate/workload) impact flow time?

Yes, it increases flow time (more WIP builds up before the bottleneck)

Does increasing demand (arrival rate/workload) impact capacity?

No, capacity remains unchanged (capacity is a design limit; it is not impacted by demand)

Does increasing demand (arrival rate/workload) impact utilization?

Yes, increases utilization at the bottleneck (utilization approaches 100%)

Does adding a parallel server at the bottleneck impact throughput?

Yes, it increases throughput

Does adding a parallel server at the bottleneck impact flowtime?

Yes, it decreases flowtime (fewer customers waiting)

Does adding a parallel server at the bottleneck impact capacity?

Yes, it increases capacity (and a new bottleneck may emerge elsewhere in the system)

Can changes at the non-bottleneck activities impact overall system utilization?

No

If demand>capacity, then utilization=

100%

If demand

demand/capacity

Flowtime=

inventory (WIP)/throughput