Computer Science UGC Net

Data mining is the discovery of useful patterns in data. Data mining are used for prediction analysis and classification- e.g; what is the likelihood that a customer will migrate to a competitor. OLAP, online analytical processing, is used to analyse historical data and its lies the business information required. OLAP are often used by marketing managers. Slice of data that are useful for marketing managers can be- How many customers between the ages 24 -25, that live in New York state, buy over $2,000 worth of groceries a month? Reporting tools are used to provide reports on the data. That are displayed to show relevance to the business and keep track of key performance indicators. Data visualization tools is used to display data from the data repository. Often data visualization is combined with data mining and OLAP tools. Data visualization can allow the user to manipulate that are to show relevancy and patterns. Clustering: Intuitively, clustering was the problem of ...

  Data Warehouse is open to an almost limitless range of definitions. Simply put, data warehouses store and aggregation of a company's data. Data warehouses are an important asset for organisations to maintain efficiency, profitability and competitive advantages, organisations collect data through many sources- online, call centre, sales needs, inventory management. The data collected have degrees values and business relevance. Figure shown below shows the architecture of a typical data warehouse and illustrate the gathering of data, the storage of data, and the quaring and data analysis support. Different steps involved in getting data into a warehouse are called as extract, transform and lode or ELT tasks; extraction refers to getting data from the sources, while loaders reference to loading the data into data warehouse. Characteristics of data warehouse: Multidimensional conceptual view Generic dimensionality Unlimited dimensions and aggregation le...

The object oriented approach views off problem in terms of objects involved rather than procedure for doing it. Object oriented program names is defined as a method of implementation in which programs organised are cooperative collections of objects, each of which is an instance of some class. The following general concept of oops are: 1) Object 2) Class 3) Data abstraction 4) Data encapsulation 5) Polymorphism 6)  Dynamic binding 7) Message passing 8) Inheritance 1) Object :  Object is an entity that can Store send and receive messages and an instance of a class. Each object contains both data and code to manipulate the data objects can interact without having to know details of each objects Data and code. For eg: person, place and table etc. 2) Class :  A class is a collection of objects that share common properties and relationships. For example you can think of a buses as objects. They have characteristics like steering wheel, motor, ...

Computer Network means an interconnected collection of autonomous computers. Two computers are said to be interconnected if they're able to exchange information and they use transmission media like copper, fibre optics , microwave etc. Features of Computer Networks : 1) Resource sharing 2) High reliability 3) Saving Money 4) Scalability 5) Communication Medium Uses of Computer networks : 1) For people, video conferencing, person to person communication through computer network. 2) Accessing for remote information 3) For interactive entertainment like video on demand and playing game. 4) It is used for social issues. Data communication: Data communication based transfer data from one point to another and in other words data communication means of transport data from source to destination. The data is transmitted from source to destination through a transmission medium in a form of electromagnetic waves. The transmission medium either guid...

Database :  It is a collection of related data that contains information about one particular enterprise. DBMS ( Database Management System):  It is a software system that allows data contained in a database. The objective of DBMS is to provide an easy method of defining, storing and retrieving information contained in database. Characteristics of database approach : In the database approach a single repository of data is maintained that is define once and then accessed by various users. In file systems, each application is free to name that are elements independently. In contrast in a database the names or levels of data define once and used used repeatedly by queries, transactions, applications. The main characteristics of database approach versus the file processing approach are the following: Self describing nature of a database system Insulation between programs and data, data abstraction Support of multiple views of the data Sharing of data and multi user tr...

A compiler is a program that reads a program written in one language, the source language and translate into an equivalent program in another language that is target language.                                 C ompiler view Compilers are sometimes classified as single pass, multi pass, load-and-go, debugging or optimising, depending on how they have been constructed. Bootstrap compiler : For bootstrapping, a compiler is characterized by 3 languages; the source language "S" that compile the target language "T" that generates code for and implementation language "I" that it is written in. We represent them using following diagram: Phases of a compiler: conceptually compiler operates in phases, each of which transforms the source program from one representation to another.  the first three pages from the bulk of the analysis portion of a compiler. Lexical analysis: in a com...

Propositional or boolean logic: Basically logics are of two types; propositional logic and predicate logic. Proposition is an assertion which is either true or false but cannot be both at same time. Eg: 1. 3+4=7 2. 19 is a prime number 3. Earth is rectangular in shape In this statement 1 and 2 are proposition but 3rd is not bcoz it's false statement. This is assertion not proposition and this is called linear paradox. Basic logic operations on proposition: 1.)Conjunction: Let p and q are two propositions.Conjunction is described by a word " and" . Truth table for and gate is:   2. Disjunction: it is described by "or" . Truth table for or is: 3. Negation: It is represented by tilde ~. Truth table is: 4. Implication: Represented by =>.