EXAM 3: Quiz 5
Which of the following statements is correct about complete enumeration?
All possible alternatives are evaluated and compared to pick the best solution
The prime objective of PAC is:
Executing MPC plans
A CR (Critical ratio) > 1 of a job implies that the job is already late.
False
At any time, if a set of n jobs is to be scheduled on m machines, there are (n*m) ways to schedule the jobs.
False
Dispatching involves the use of logic that guides the prioritizing of jobs at a workstation. These rules are referred to as lot-sizing rules.
False
In MRP, the only source of uncertainty is supply.
False
In a single machine job shop, the makespan depends on the rule used for scheduling.
False
Johnson's rule when applied in a two-machine case will provide minimum average lateness.
False
Johnson's rule will minimize average job completion (flow) time in two machine case
False
KBB will provide the minimum total cost only if the net requirements in MRP are lumpy.
False
Lead times are typically made up of operation or machine run time per piece × lot size.
False
PAC stands for Process Activity Control
False
POQ with T > 1 will minimize inventories
False
The Critical Ratio rule uses the information about the processing time of the job in the current work center only.
False
The economic order quantity (EOQ) lot-sizing technique uses the "square root formula" to balance setup cost, carrying cost, and cost of stockouts.
False
The primary consideration in the development of lot-sizing procedures for MRP is the nature of the gross requirements data.
False
The reason KBB gives the guaranteed optimal solution is because it explicitly evaluates all possible combinations and selects the best.
False
There is no cure for reducing MRP nervousness.
False
Priority sequencing rules determine which of the following? I- Allocation of goods to customers II- Which machine to service next? III- Which job to work on at the work center?
III only
Which one of the following lot-sizing rules guarantees an optimal solution in a general MRP environment?
KBB
Which one of the following lot-sizing rules guarantees an optimal solution when demand is constant?
KBB & EOQ
Freezing the schedule is one way of mitigating
MRP system nervousness
The total time to process an entire set of jobs at a work center is referred to as
Make-span
Which of the below activities in MPC provide direct input to PAC?
Material Requirements Planning
Summing the setup times and run times for all remaining operations, and subtracting this from the time remaining until the due date is referred to as
Order Slack (ST) rule
The lowest planning and control level in MPC is:
PAC
A critical information service provided by MRP is apprising the SFC systems of all changes in material plans
True
A small change caused by a relatively minor shift in the MPS may amplify the explosion process and use of the discrete lot-sizing procedures.
True
In a one machine system, the EDD rule for sequencing the order of jobs will result in minimizing average lateness
True
POQ and LFL will be the same if TBO = 1 period.
True
The SPT rule represents the best way to pick the next job to run, if the objective is to minimize average time per job, to minimize average number of jobs in the system, or to minimize average job lateness.
True
The average time in the system is directly related to work-in-process inventory and average number of jobs in the system.
True
The lot-sizing procedure used for a parent part in an MRP system has a direct impact on the gross requirements data passed to its component parts.
True
The manufacturing lot-size problem is basically one of converting requirements into a series of replenishment orders in the planning horizon.
True
The primary PAC objective is managing the materials flow to meet MPC plans
True
The quantities and timings for planned order releases are determined via MRP logic using the inventory records, the gross requirements data, and a quantity-determination (lot-sizing) procedure.
True
When several jobs arrive at a work center, there is a need for
a system of scheduling and prioritizing
The general objective of all MRP lot-sizing procedures is to
balance inventory-related costs to achieve a low total cost requirement schedule.
The lot-for-lot (L4L) procedure
creates order quantities that are exactly equal to net requirements.
Which of the following statements is correct about implicit enumeration?
only promising alternatives are judiciously selected & evaluated.
One way of dealing with the shop-floor complexity is by
priority sequencing rules
Examining realistic, multiple-machine, dynamic scheduling situations is possible by using
simulation
Sequencing rules are used to establish
the priorities for the jobs in a queue waiting to be processed at a work center.
