In computer science, a data structure is a data organization, management, and storage format that enables efficient access and modification. More precisely, a data structure is a collection of data values, the relationships among them, and the functions or operations that can be applied to the data.

The Big O notation estimates the execution time of an algorithm in relation to the input size. Algorithm analysis is focused on growth rate. The multiplicative constants have no impact on growth rates. Algorithm analysis is for large input size. If the input size is small, there is no significance to estimate an algorithm’s efficiency.

Iterator is a classic design pattern for walking through a data structure without having to expose the details of how data is stored in the data structure. Each collection is Iterable. You can obtain its Iterator object to traverse all the elements in the collection.

Data link layer has responsibility of transferring data (a frame) from one node to adjacent node over a link. Make sure the transition is error-free. It needs to check the error.

Transport Layer is responsible to data delivery. We need to maintain a stable data transfer. Many functions of the transport layer is similar to those offered by the data link layer. The key differenece is, Data link layer manages transport in a single network, while transport layer manages traffic across an internetwork (end-to-end delivery).

Android is a mobile operating system based on a modified version of the Linux kernel and other open source software, designed primarily for touchscreen mobile devices such as smartphones and tablets.

The basic unit of an Android application is an activity, which displays the UI of your application. The activity may contain widgets such as buttons, labels, textboxes, and so on.

When an object vibrates, and we plot the variation of air pressure at some point in vicinity against time, we obtain a waveform. All periodic waveforms (e.g. square, sawtooth, ..etc.) can be broken down into a combination of weighted sine waves each of which is called a frequency component of the waveform.

The major objective of image coding is to represent an image with as few bits as possible while preserving the level of quality and intelligibility required for the given application. Quality of image is given with repect to the human observation. Therefore it is a more subjective stuff.

The basic unit of an Android application is an activity, which displays the UI of your application. The activity may contain widgets such as buttons, labels, textboxes, and so on.