Enumeration Flashcards
Assumptions in Sequencing Problem (NTWET)
- No machine may process more than one job simultaneously.
- There is only one machine of each type.
- While processing, no job is given priority.
- Each job once started on the machine, the processing shouldn’t stop in the middle.
- The given processing time includes the transfer time and setup time.
(4) Types of Sequencing Problem
- n jobs are to be processed on 2 machines
- n jobs are to be processed on 3 machines
- n jobs are to be processed on m machines
- 2 jobs are to be processed on m machines
(2) Methods of Solving 2 jobs on m machines
- By enumerative method
- By graphical methods
Failure mechanisms can be
- gradual failure
- due to wear and tear
- sudden failire
Sudden failure may be
- retrogressive failure
- progressive failure
- random failure
The Bathtub Curve
- infant stage or early failure stage
- youth stage or random failure stage
- old stage or wear our failures
(4) types of replacement problems
- Replacement of capital equipment
- Replacement of Items that fail completely
- Replacement of human beings in organization or staffing problem
- Miscellanous problems
(5) Replacement of items whose efficiency reduces or maimtenance cost increases with time or due to age and money value is NOT CONSIDERED
- Cost consideration
- Efficiency Measurement
- Maintenance cost
- Alternative Choices
- Techniques for analysis
(3) Techniques for analysis
- Replace items with INCREASING maintenance cost over time, with CONSTANT money value
- Replace items with INCREASING maintenance cost over time, with CHANGING money value
- Use the concept of PRESENT VALUE to compare alternative choices
(2) the criterion is:
- do not replace if operating cost of next period is LESS THAN the weighted average of previous period
- replace if operating cost of the next period is GREATER THAN the weighted aversge of previous period
(2) Replacement of items that FAIL COMPLETELY and SUDDENLY are EXPENSIVE to be replaced
- individual replacement policy
- group replacement policy
(4) Classifications of inventory
- raw materials (direct or indirect)
- work in process
- finished goods
- maintenance, repair, and overhaul
(3) Inventory Management Technique
- just-in-time
- economic order quantity
- abc analysis
Inventory Control System
- periodic inventory management system
- perpetual inventory management system
Inventory costing method
- fifo (firsr in first out)
- lifo (last in first out)
- weighted average
Inventory Performance Metrics
- inventory turnover ratio
- days sales of inventory
- fill rate
Challenges and solutions
- stockouts
- overstocking
- obsolescenes
Importance of effective inventory control
- Minimize expenses associated with excessive inventory.
- Freeing up tied up capital in excessive inventory
- Facilitate financial reporting and compliance to regulatory requirements
- Respond quickly to market changes and customer demands
- Maintaining optimal inventory control levels
- Enhances operational efficiency
- Mitigate risks
Recommendation for further research
- Supply Chain Resilience
- Inventory Managament in E-Commerce
- Collaborative Inventory Management
- Inventory Forecasting Models
- Human Factors
- Sustainable Inventory Practices
(4) basic structures of waiting line
- single channel single phase
- single channel multiple phase
- multiple channel multiple phase
- multiple channel single phase
(2) possible situations for a customer to acquire the service needed
- Customer to service facility
- Service facility to customer
Queueing process
Arrival
Waiting line
Unit is being served
Leaving the queue
Size of arrival
Finite and infinite
Capacity of the system
Limited and unlimited
Distribution of service (inter-arrival time)
Negative exponential distribution
Erland or Gamma distribution
Customer behaviour
Balking
Reneging
Collusion
Jockeying
Queue or Service Discipline
- fifo
- lifo
- service by random order (siro)
- service by priority (preemptive or non preemptive)
Queue system (state)
Steady state
Transient state
Explosive state
Queue Models
- probabilistic queueing model
- deterministic queueing model
- mixed queueing model
