The operations research expert has a wide array of methods and techniques available for solving problems.

**Linear Programming.** Linear Programming (LP) is a mathematical
technique of assigning a fixed amount of resources to satisfy a number
of demands in such a way that some objective is optimized and other
defined conditions are also satisfied.

**Transportation Problem.** The transportation problem is a special
type of linear programming problem, where the objective is to minimize
the cost of distributing a product from a number of sources to a number
of destinations.

**Assignment Problem.** Succinctly, when the problem involves
the allocation of *n* different facilities to *n* different
tasks, it is often termed as an assignment problem.

**Queuing Theory.** The queuing problem is identified by the
presence of a group of customers who arrive randomly to receive some
service. This theory helps in calculating the expected number of people
in the queue, expected waiting time in the queue, expected idle time
for the server, etc. Thus, this theory can be applied in such situations
where decisions have to be taken to minimize the extent and duration
of the queue with minimum investment cost.

**Game Theory.** It is used for decision making under conflicting
situations where there are one or more opponents (i.e., players).
In the game theory, we consider two or more persons with different
objectives, each of whose actions influence the outcomes of the game.
The game theory provides solutions to such games, assuming that each
of the players wants to maximize his profits and minimize his losses.

**Inventory Control Models.** It is concerned with the acquisition,
storage, handling of inventories so as to ensure the availability
of inventory whenever needed and minimize wastage and losses. It help
managers to decide reordering time, reordering level and optimal ordering
quantity.

**Goal Programming**. It is a powerful tool to tackle multiple
and incompatible goals of an enterprise.

**Simulation.** It is a technique that involves setting up a
model of real situation and then performing experiments. Simulation
is used where it is very risky, cumbersome, or time consuming to conduct
real study or experiment to know more about a situation.

**Nonlinear Programming.** These methods may be used when either
the objective function or some of the constraints are not linear in
nature. Non-Linearity may be introduced by factors such as discount
on price of purchase of large quantities.

**Integer Programming.** These methods may be used when one or
more of the variables can take only integral values. Examples are
the number of trucks in a fleet, the number of generators in a power
house, etc.

**Dynamic Programming.** Dynamic programming is a methodology
useful for solving problems that involve taking decisions over several
stages in a sequence. One thing common to all problems in this category
is that current decisions influence both present & future periods.

**Sequencing Theory.** It is related to Waiting Line Theory.
It is applicable when the facilities are fixed, but the order of servicing
may be controlled. The scheduling of service or sequencing of jobs
is done to minimize the relevant costs. For example, patients waiting
for a series of tests in a hospital, aricrafts waiting for landing
clearances, etc.

**Replacement Models**. These models are concerned with the problem
of replacement of machines, individuals, capital assets, etc. due
to their deteriorating efficiency, failure, or breakdown.

**Markov Process.** This process is used in situations where
various states are defined and the system moves from one state to
another on a probability basis. The probability of going from one
state to another is known. This theory helps in calculating long run
probability of being in a particular state.

**Network Scheduling-PERT and CPM.** Network scheduling is a
technique used for planning, scheduling and monitoring large projects.
Such large projects are very common in the field of construction,
maintenance, computer system installation, research and development
design, etc. Projects under network analysis are broken down into
individual tasks, which are arranged in a logical sequence by deciding
as to which activities should be performed simultaneously and which
others sequentially.

**Symbolic Logic.** It deals with substituting symbols for words,
classes of things, or functional systems. It incorporates rules, algebra
of logic, and propositions. There have been only limited attempts
to apply this technique to business problems; however, it is extensively
used in designing computing machinery.

**Information Theory.** It is an analytical process transferred
from the electrical communications field to operations research. It
seeks to evaluate the effectiveness of information flow within a given
system and helps in improving the communication flow.