*2.4.4.2 MTTR (average time to repair)*

When errors occur, the times are needed to fix the errors. Mean MTTR is the average time it takes to track and repair the errors that cause the system to fail.

MTTR is the average time to replace the elements that were defeated. When a hardware element fails, then the failure occurs permanently, and the MTTR will spend time repairing and replacing a new element.

#### *2.4.4.3 Average time between two failures (MTBF)*

To get MTBF, we need to combine MTTF and MTTR. A 300-h MTBF is a failure. The next failure occurs only after 300 h. In this case, time measurement is timely.

**105**

*ANFIS to Quantify Maintenance Cost of IT Services in Telecommunication Company*

A probability that a system fails against a request. In POFOD 0.001 it means that, 1 out of 1000 requests may lead to failure. The POFOD is an important measure for the security of critical systems and should be kept as low as possible.

This metric is sometimes referred to as failure. The number of repetitions of behavior is unpredictable. ROCOF 100/2 means 2 failures that are likely to occur per 100 operating times. This is related to operational systems or process flow systems when the system should execute a significant amount of similar requests like a

Availability makes it possible for a system to be available at a specific time. Availability of 0.998 means that every 1000 times the system unit is probably avail-

To evaluate performance, we have three techniques that are as follows:

An early technique is important for analysis, simulation, and modeling and

Simulation involves creating a model for the behavior of a system and advancing it with an appropriate look at the workload. The benefits of it are general and flex-

It should be decided what the level of simulation does not simulate. Doubling the

minor behaviors of a system is often unnecessary, and its high cost is forbidden. Simulation as well as measurement also produces many raw data that should be analyzed using statistical techniques. Simulation is also necessary, as measurement

In simulation, as well as measurement, only the behavior of a system is deter-

An analytical modeling is the creation of a mathematical model of the system's behavior and its solution. Its advantages over the two previous ones are as follows: (1) creating a good attitude to the work of a system that is valuable, even if the

works well for hardware, software, and linking patterns.

ible, which should be considered in order to simulate the following:

by a carefully experienced design, to reduce the cost of maintenance.

mined for the stench of inputs by the results obtained from data analysis.

*DOI: http://dx.doi.org/10.5772/intechopen.82827*

*2.4.4.5 Failure rate (ROCOF)*

credit card process system.

*2.4.4.6 Accessibility (AVAIL)*

**2.5 Performance evaluation**

3.Analytical modeling

*2.5.1 Measurement technique*

*2.5.2 Simulation software technique*

*2.5.3 Analytical modeling technique*

able for 998 times.

1.Measure

2.Simulation

*2.4.4.4 Possibility of failure in demand (POFOD)*

*ANFIS to Quantify Maintenance Cost of IT Services in Telecommunication Company DOI: http://dx.doi.org/10.5772/intechopen.82827*

## *2.4.4.4 Possibility of failure in demand (POFOD)*

A probability that a system fails against a request. In POFOD 0.001 it means that, 1 out of 1000 requests may lead to failure. The POFOD is an important measure for the security of critical systems and should be kept as low as possible.

#### *2.4.4.5 Failure rate (ROCOF)*

*Maintenance Management*

the failure.

tory failure.

*2.4.3 Usability of the system*

of parts, tools, manpower, and hardware.

of field of use and initial experience [10].

*2.4.4 Accessibility metrics and reliability*

*2.4.4.1 Average time to failure of (MTTF)*

*2.4.4.2 MTTR (average time to repair)*

spend time repairing and replacing a new element.

*2.4.4.3 Average time between two failures (MTBF)*

product [9].

regulatory failure, which can lead to preventive and corrective maintenance of

3.**Operational availability:** When an item works satisfactory, is employed at a point in time and used in a reasonable logic operation and regulatory environment Including logistic time, preparation time, waiting, or regula-

It both contains corrective and preventive maintenance. Its calculation includes the average time between failures, which is divided by the sum of the average time between failure and the average MDT breakdown. This size defines the availability of elements that are controlled by logistics and extends planners, such as the quality

Non-quality usability and the amount of information used to rely on resources

[7, 12]. Culnan [10] has come to the idea that the requirements for collecting information related to the occupation, and occupation of each person may limit access to resources. The ability to use resources generally defines both the social and economic costs associated with communicating information. The online information system is evaluated in two dimensions, including usability and ease of use. Usability is related to the physical and informational dimension or grammatical language. When a new system is introduced, the user needs to be trained and supported to be able to get familiar with the system's command language. Usability can play an important role in influencing an individual to select an information source from among other suggested sources. Usability is likely to be affected by two types

Reliability and availability metrics are used to measure them in a software

MTTF 500 means that a failure can happen every 500 times. The time units are completely system-dependent and can even be identified in a large amount of transactions. MTTF is related to a system with long transactions. When the system

When errors occur, the times are needed to fix the errors. Mean MTTR is the average time it takes to track and repair the errors that cause the system to fail. MTTR is the average time to replace the elements that were defeated. When a hardware element fails, then the failure occurs permanently, and the MTTR will

To get MTBF, we need to combine MTTF and MTTR. A 300-h MTBF is a failure. The next failure occurs only after 300 h. In this case, time measurement is timely.

processes take a lot of time, MTTF should be longer than transactions.

**104**

This metric is sometimes referred to as failure. The number of repetitions of behavior is unpredictable. ROCOF 100/2 means 2 failures that are likely to occur per 100 operating times. This is related to operational systems or process flow systems when the system should execute a significant amount of similar requests like a credit card process system.

#### *2.4.4.6 Accessibility (AVAIL)*

Availability makes it possible for a system to be available at a specific time. Availability of 0.998 means that every 1000 times the system unit is probably available for 998 times.

#### **2.5 Performance evaluation**

To evaluate performance, we have three techniques that are as follows:


#### *2.5.1 Measurement technique*

An early technique is important for analysis, simulation, and modeling and works well for hardware, software, and linking patterns.

#### *2.5.2 Simulation software technique*

Simulation involves creating a model for the behavior of a system and advancing it with an appropriate look at the workload. The benefits of it are general and flexible, which should be considered in order to simulate the following:

It should be decided what the level of simulation does not simulate. Doubling the minor behaviors of a system is often unnecessary, and its high cost is forbidden.

Simulation as well as measurement also produces many raw data that should be analyzed using statistical techniques. Simulation is also necessary, as measurement by a carefully experienced design, to reduce the cost of maintenance.

In simulation, as well as measurement, only the behavior of a system is determined for the stench of inputs by the results obtained from data analysis.

#### *2.5.3 Analytical modeling technique*

An analytical modeling is the creation of a mathematical model of the system's behavior and its solution. Its advantages over the two previous ones are as follows: (1) creating a good attitude to the work of a system that is valuable, even if the

model has a complex solution. (2) Simple analytic modeling can often be solved simply and obtains an exciting result. (3) The results of analytical modeling are much better than the previous two measurements, which can be predicted.
