Notes, summaries, assignments, exams, and problems for Computers

Fundamental Concepts in Knowledge and Data

• The most fundamental combiner is the unification of the Self with itself, which gives rise to the knower, the process of knowing, and the known.
• Normalization is a mathematically interesting, bottom-up technique for producing a set of relations with desirable properties from a set of mathematical dependencies in the data.
• A graphical technique employed by Vedic science is the unified field chart, which provides a holistic overview of a discipline and links all knowledge with the Self.

Data Compression Techniques

Variable-Length Integer Coding (VarInt)

A simple approach to compression is to use only as many bytes as necessary to represent an integer. This technique is known as variable-length integer coding... Continue reading "Core Concepts in Data Processing and Information Retrieval" »

Define SDLC models? What are the most known SDLC model?

An SDLC model defines implementation of an approach to the project. It defines the various processes, and phases that would be carried out throughout the project to produce the desired output. There are a variety of SDLC models that exist catering to different needs and characteristics of a project. Some are of iterative nature (Prototyping), whereas some are sequential (waterfall).

Some of the well-known SDLC models are:
Waterfall model, Software prototyping, Rapid application development,

Extreme programming, and End user development. 

List Advantages of using system analysis and design techniques in approaching computerized info system?

• Identifies and solves the right problems
• Implement

Binary Search Tree (BST)

Binary search tree (BST) is a tree in which all nodes follow the below mentioned properties:

1. The left sub-tree of a node has a key less than or equal to its parent node's key.
2. The right sub-tree of a node has a key greater than or equal to its parent node's key.
3. Binary search tree (BST) divides all its sub-trees into two segments: left sub-tree and right sub-tree and can be defined as left_subtree (keys) ≤ node (key) ≤ right_subtree (keys).

Red-Black Tree

A red-black tree is a binary search tree in which each node is colored red or black. The root is black. The children of a red node are black. Every path from the root to leaf has the same number of black nodes and all leaves are black.

AVL Tree

Adelson, Velski & Landis

1. The performance of a client-server system is strongly influenced by two major network characteristics: the bandwidth of the network (that is, how many bits/sec it can transport) and the latency (that is, how many seconds it takes for the first bit to get from the client to the server). Give an example of a network that exhibits i) high bandwidth but also high latency, and ii) then give an example of one that has both low bandwidth and low latency. i) High bandwidth but also high latency: A transcontinental fiber link might have many gigabits/sec of bandwidth, but the latency will also be high due to the speed of light propagation over thousands of kilometers. Similarly, a satellite link may run at megabits/sec but have a high latency to... Continue reading "Understanding Network Characteristics and Protocols" »

Evolution of the iPhone

Released on June 29, 2007, the iPhone has seen multiple new hardware iterations with new iOS releases since.

User Interface and Connectivity

The user interface is built around the device's multi-touch screen, including a virtual keyboard. The iPhone has Wi-Fi and can connect to cellular networks.

Core iPhone Features

An iPhone can:

• Shoot video (standard feature from the iPhone 3GS)
• Take photos
• Play music
• Send and receive email
• Browse the web
• Send and receive text messages
• Follow GPS navigation
• Record notes
• Perform mathematical calculations
• Receive visual voicemail

Other functionality, such as video games, reference works, and social networking, can be enabled by downloading mobile apps.

The App Store Ecosystem

As of January 2017, Apple'... Continue reading "Evolution of the iPhone: Early Models & Capabilities" »

public Class HashSet1

    implements IHashSet1

{   private IHashTable hashTable;

    private static final Object PRESENT = new Object();

    public HashSet1() {hashTable = new HashTable1();}

    public boolean add(Object o) {

        return hashTable.Put(o, PRESENT)==null;}

    public void clear() {hashTable.Clear();}

    public boolean contains(Object o) {

        return hashTable.ContainsKey(o);

}    public boolean containsAll(IHashSet1 s) {

        Iterator e = s.iterator();

        while(e.HasNext()) {

            if(!Contains(e.Next())) {

                return false;

            }

        }

        return true;

    }

    public boolean equals(Object... Continue reading "Java HashSet1 Implementation Using HashTable" »

Connected and Disconnected Graphs

A graph is connected if any two vertices of the graph are connected by a path. Conversely, a graph is disconnected if at least two vertices are not connected by a path.

If a graph G is disconnected, then every maximal connected subgraph of G is called a connected component of graph G.

Dense and Sparse Graphs

A dense graph is a graph in which the number of edges is close to the maximal possible number of edges.

A sparse graph is a graph in which the number of edges is close to the minimal possible number of edges. A sparse graph can be a disconnected graph.

Key Characteristics and Comparison

• Informally, a graph with relatively few edges is sparse, and a graph with many edges is dense.
• Sparse graphs are sparsely connected

Here's a breakdown of key characteristics and differences between TCP and UDP protocols:

• TCP and UDP sockets are created by the transport layer: False
• Before any data exchange takes place between two UDP applications, a logical connection must be established between them: False
• Both SMTP and POP3 are TCP based: True
• The UDP segment contains a checksum: True
• The TCP segment contains a checksum: True
• UDP makes use of the Selective Repeat protocol: False
• The Selective Repeat algorithm is used for congestion control: False
• HTTP uses TCP as its underlying transport protocol: True
• With POP3, the email message is always deleted from the mail server if the client downloads the email message to its local email client application: False
• Only TCP uses port numbers,

Computer Data Storage

Computer data storage, often called storage or memory, refers to computer components, devices, and recording media that retain digital data used for computing for some interval of time. Computer data storage provides one of the core functions of the modern computer: information retention. It is one of the fundamental components of all modern computers and, coupled with a central processing unit (CPU, a processor), implements the basic computer model used since the 1940s.

In contemporary usage, memory usually refers to a form of semiconductor storage known as random access memory (RAM) and sometimes other forms of fast but temporary storage. Similarly, storage today more commonly refers to mass storage: optical discs, forms... Continue reading "Understanding Computer Data Storage: Memory and Mass Storage" »