Friday, 12 June 2020

Unit-7 : Multimedia (Notes of TU BSc. 4th Year Computer Science)

Multimedia

Syllabus: What is Multimedia? What is Multimedia Computer System? Multimedia Components (Text, Graphics, Animation, Audio, and Video) Multimedia Applications 




Multimedia is the field concerned with the computer-controlled integration of texts, graphics, drawings, videos, animation, audio, and any other media where every type of information can be represented, stored, transmitted, and processed digitally. Multimedia must possess the following four basic characteristics;
  1. Must be computer-controlled
  2. Should be integrated
  3. Must represent information digitally
  4. Must provide an interactive interface to presentation

A multimedia application is an application that uses a collection of multiple media sources. Example: text, graphic, image, audio, animation, and video. It can be divided into three categories,
  1. Information System
  2. Remote Representation
  3. Entertainment

Multimedia Computer System
A multimedia computer system is a computer system capable of processing multimedia data and applications. Multimedia computer system is capable of processing and interpreting two or more components of multimedia which includes text, graphic, animation, audio, and video. One of the main requirements of multimedia systems is real-time operation. Multimedia computer system usually requires a fast processor, large storage, graphic cards, and fast input/output devices.


Multimedia Components
As multimedia is a combination of more than one type of media or elements, key elements of multimedia are as follows:

Text
It is basic for word processing programs and is still the fundamental information used in many multimedia programs. In fact, many multimedia applications are based on the conversation of a book to a computerized form.
Text is a combination of alphabet symbols, digits, punctuations, etc. In multimedia applications, other media or screens can be linked through the use of text. This is called hypertext. Text in a multimedia system can express specific information or it can act as support for the information contained in other media items.

Data say textual or numerical is easy to represent using general characters but it is difficult to represent in computers so binary digit coding for text representation is IRA (International Reference Alphabet) coding. It is also called the ASCII code. UNICODE is another mechanism that includes larger sets of characters and uses 16 bits for each character.

Graphics (Images)
It refers to any computer program that makes a computer capable of displaying and manipulating pictures. Graphics make the multimedia application attractive and help to illustrate ideas through static pictures. Digital image files use a variety of formats and file extensions. Among the most common are JPEG, GIFs, PNG, etc.
Graphics design software such as photoshop and point.net allows developers to create complex visual effects with digital images. There are two types of graphics used:

I) Bitmaps (Raster images)
An image is represented as a two-dimensional array of “spots” (pixels). Pixel stands for picture element and is the smallest element of the monitor. Every pixel is represented by a group of bits. Therefore it is also called the “bitmap” image.
It can contain any number of colors but we distinguish between four main categories:
  1. Linear - only two-color (black and white)
  2. Grayscale image - (pure black and white)
  3. Multi tones - (two or more colors)
  4. Full-color images - (RGB, CMYK)
The size of raster images is determined by the following two factors, a) resolution and b) color depth.

II) Vector graphics
An image is represented as a collection of straight and curved line segments. Here the image is described as a collection of line segments. Vector images are simply combinations of lines and curves. CDR, PS use vector images.

Audio
It has a greater role to play in multimedia development. It gives life to the static of multimedia. Incorporation of audio is one of the most important features of multimedia which enhances multimedia usability. 
The application of audio service is telephone communication, telemarketing, voice mail, entertainment radio, etc. Audio formats include MP3, WMA, Wave, MIDI.
The quality of sound is characterized by bandwidth used. Voice of telephone uses 3000Hz of bandwidth, the voice of teleconferencing used 7000Hz and for better quality 15000Hz is used.
A sound wave is characterized by the following characteristics:
  • Amplitude
  • Frequency
  • Bandwith

Videos
Video clips can be combined with the audio, text, graphics for multimedia presentation. Video is the sequence of images over time. Video conferencing, television, multimedia, CCTV, etc. are the application of video communication. The size of the video is much higher than that of the image. Common digital video formats include flash, MPEG, MP4, AVI, etc. which re actually compression techniques used with videos.

Animation
It is a simulation of movement created by displaying a series of pictures or frames. Cartoons on television are one example of animation. Animation on computers is one of the chief ingredients of multimedia presentations.
Video is live or real footage of an event taken with a video camera. But animation is a computer-generated moving picture produced in either two or three dimensions by using the software.
  • It can draw the user’s attention and can also explain the things in detail and a better way.
  • It can help users to visualize the 3D nature of the object.
The most common tool for creating animations is Adobe Flash.


Applications of Multimedia
We are familiar that using multimedia makes things clear, easier to understand, and more informative. Some of the areas are:
  1. Education and Training: Computer Based Training (CBT) is a type of multimedia product which allows users to learn at their own pace.
  2. Product Promotion: Advertising is perhaps one of the biggest industries that use multimedia to send their message to the masses.
  3. Engineering: Computer-Aided Design (CAD) is used by engineers where they can view the design from many aspects and improve on it before production.
  4. Leisure and Entertainment: Multimedia systems designed for leisure and entertainment are generally classified as computer games.
  5. Information Provision: A multimedia encyclopedia is an example of a multimedia system used to provide information.
  6. Virtual Reality and Simulations: Flight simulators are used to train pilots.
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Unit-6 : Database Management System (Notes of TU BSc. 4th Year Computer Science)

Database Management System

Syllabus: What is Database? What is Database Management System? Advantages of using Database Approach; Database applications; Introduction to Database Models; Introduction to data warehousing, Data mining, and Data Mart; Computational Nano Science; Space Data; Computational Biology  


A database is an organized collection of logically related data that contains information relevant to an enterprise. For example, the university database maintains information about students, courses, and grades.

Database Management System (DBMS) 
A database management system (DBMS) is the set of programs that are used to store, retrieve, and manipulate the data in a convenient and efficient way. The main goal of DBMS is to hide the complexities of data management from users and provide an easy interface to them. Examples of DBMS structures are Oracle, Sybase, Microsoft SQL Server, Dbase, etc.
The database management system that maintains a relationship between multiple data files is called Relational Database Management System (RDBMS).

Advantages of using Database Approach
Drawbacks of the flat-file systems are solved by DBMS. Some of the advantages of DBMS are:
  1. Data Redundancy - Data redundancy means duplication of the same data or data files in different places. Flat file systems suffered from the problems of high data redundancy which leads to higher storage and access cost. DBMS can greatly reduce the problem of data.

  1. Data Inconsistency - Data inconsistency is a side effect of data redundancy. Data is said to be inconsistent if various copies of the same data may no longer agree. Data inconsistency occurs if changed data is reflected in data files in one place but not elsewhere in the system. For example, if library data contain a cell number of a student as 98******55 but examination data file stores 98******53 as cell number of the student then we can say that the data is inconsistent.
  2. Data Isolation - Isolation is the act of separating something. Because data are scattered in various files and files may be in different formats, writing new application programs to retrieve the appropriate data is difficult in a flat-file system. For example, one data file may contain data separated from commas and another file may contain data separated by white space.
    Database management systems provide shared access to centrally stored data therefore it is easy for application programs to retrieve required data from a centralized database.
  3. Difficulty in Accessing Data - File processing systems do not allow the required data to be retrieved in an efficient and convenient way. For example, assume we already have a program to generate the list of books on the basis of the subject. Now, if we need to generate the list of books on the basis of the author's name, either we need to extract the data from book data files manually or we should request the programmer to write a program to retrieve the required data from the book data file. Both the alternative is not satisfactory but in a database system, it is very easy to write general programs to generate different lists on the basis of different criteria.
  4. Integrity Problems - Integrity means the correctness of data before and after the execution of a transaction. Integrity constraints are condition applied to the data which are imported to maintain the correctness of data.
    Database management systems allow us to specify integrity constraints on data. Therefore it is easy to maintain the correctness of data.
  5. Atomicity Problems - Execution of transaction must be atomic. This means transactions must execute at its entirely or not at all. If the execution of the transaction is not atomic, it leaves the database an incorrect state.
    Database management systems guarantee the atomicity of execution of transaction.
  6. Concurrent Access Anomalies - Concurrent updates to the same data by different transactions at the same time may result in inconsistent data. For example, consider bank account ’n’ containing Rs. 50,000. If two customers withdraw funds say 15,000 and 20,000 respectively from account A at about the same time, the result of the concurrent execution may leave the account in an inconsistent state.
    Database systems support concurrent execution of transaction on the same data without resulting in inconsistent data.
  7. Security Problems - In a database system, we may create different user accounts and provide different authorization to different users. Thus we are able to hide certain information from some users.
    For example, in a banking system, payroll personnel need to see only that part of the database that has information about various bank employees.

Database Applications
DBMS is widely used in various areas because of its numerous advantages. Some of the most common database applications are listed here.
  1. Airlines and Railways - They use an online database for reservation and for displaying and schedule information.
  2. Banking - Banks use databases for customer inquiry, accounts, loans, and other transactions.
  3. Education - Schools and colleges use the database for course registration, result, and other information.
  4. Telecommunications - Department of IT uses the database to restore or store information about the telecommunication network, telephone numbers, records of calls for generating monthly bills, etc.
  5. Credit Card Transaction - Database is used for keeping track of purchase on credit cards in order to get or generate monthly statements.
  6. E-commerce - Integration of heterogeneous information sources for a business activity such as online shopping, booking of holiday packages, etc.
  7. Healthcare Information Systems and Electronic Patient Record - Database are used for maintaining the patient health care details.
  8. Digital Libraries and Digital Publishing - Database is used for the management and delivery of large bodies of textual and multimedia data.
  9. Finance - Database is used to store product, customer, and transaction details.
  10. Human Resource - Organizations use a database for storing information about their employees, salaries, benefits, taxes, and generating salary cheques.

Database Models
A database model is an abstract model that describes how the data is represented and used.
It consists of a set of data structures and conceptual tools that are used to describe the structure (data, types, relationships and constraints) of a database. Traditionally, there are different database models that are used to design and develop the database of the organization.
  1. Hierarchical model
  2. Network model
  3. Entity-Relationship model
  4. Relational model
  5. Object-oriented model
  6. Object-relational model

  1. Hierarchical Model (Tree-like): The oldest type of data model developed by IBM in 1968. It is the record based representational or implementational data model.
    In this model, different records are interrelated through the hierarchical or tree-like structure.
    For example, A parent record can have several children, but a child can have only one parent. It, therefore, represents only one and one-many relationships.
  2. Network Data Model: It is an extension of the hierarchical database structure. It is also a record based representational or implementational data model.
    It is more flexible than the old data model.
    It describes data and relations between data by using a graph rather than a tree-like structure.
    In a hierarchical data model, a child cannot have more than one parent but it is allowed in-network data model.
  3. Entity-Relationship Model: It is based on a perception of the real world that consists of a collection of basic objects called entities and relationships among these subjects/objects.
    In this model, a database can be modeled as a collection of entities and relationships among entities.
    It is one of the conceptual data models and describes the information used by an organization in a way that is independent of any implementation level issues and details.
    The database can be expressed graphically by the E.R. diagram.
  4. Relational Model: It is also a representational or implementation data model. In this data model, unlike the hierarchical and network models, there are no physical links.
    All the data is maintained in the form of tables (generally known relations) consisting of rows and models.
    Thus, the relational model has become more programmers friendly and much more dominant and popular in both industrial and academic scenarios.
  5. Object-Oriented Data Model: Based on object-oriented programming paradigm, a core object-oriented data model consists of following basic object-oriented concepts.
    a) object and object identifier
    b) attributes and methods
    c) class
    d) class hierarchy and inheritance


Data warehousing
It is the process of constructing and using a data warehouse. A data warehouse repository of the information constructed by integrating data from multiple heterogeneous sources that support analytical reporting structured and decision making.
It involves data integration, data cleaning, and data consolidations.
  • Data Integration: Process of standardizing the data definition and data structures of multiple data sources.
  • Data Cleaning: Process of detecting and correcting incorrect, irrelevant, out of date, corrupt, etc.
  • Data Consolidation: Refers to the collection and integration of data from multiple sources into a single destination.
(Repository: A place which stores a large number of data)

Data Mining
Extracting information from huge sets of data. It is the process of mining knowledge from data.
Knowledge extracted from data can be used for any of the following applications such as market analysis, fraud detection, customer retention, production control, science exploration, etc.
Applications of data mining
  1. Financial Data Analysis: Banks and financial institutions use data mining for loan payment prediction, customer credit policy analysis, etc.
  2. Retail Industry: Data mining in the retail industry helps in identifying customer buying patterns and trends that lead to improved quality of customer service.
  3. Telecom Industry: In the telecommunication industry, data mining helps in identifying telecommunication patterns.
  4. Biological Data Analysis: Data mining is a very important part of bioinformatics.
  5. Other scientific application
  6. Industrial Detection

Data Mart
Datamart is a subject-oriented archive that stores data and uses the retrieved information to assist and support the requirements involved within a particular business function or department. Data marts exist within a single organizational data warehouse repository.
A data mart is basically a condensed and more focused version of a data warehouse that reflects the regulations and processed specifications of each business unit within an organization. Each data mart is dedicated to a specific business function or region. This subset of data may span across many or all of an enterprise’s functional subject areas.

Computational Nanoscience
It is the field that is concerned with modeling of large scale computer simulation in order to understand the new nanoscale phenomena and regime. In nanotechnology, the numbers are especially important because things are to be built and require very high accuracy. Nanosystem presents a new type of multi-scale modeling and algorithmic time and storage challenges.
Hardware and software tools to solve some of the nanoscience modeling problems already exist. Software tools and application-oriented computer programming languages that already exist must be assembled and investigated for their suitability in solving nanosystem problems.
Molecular Workbench (MW) is another tool used in computational nanoscience.

Space Data
Data collected from space with the help of a satellite is called space data. May be data about weather conditions, data about other planets, data about different areas like forest, oceans, etc.
Space Data Routers (SDR) will allow space agencies, academic institutes, and research centers to share space data generated by single or multiple missions.

Computational Biology
It is the science of using biological data to develop algorithms and relations among various biological systems. It involves the development and application of data analytical and theoretical methods, mathematical modeling, and computational simulation techniques to the study of biological behavioral and social systems. It spans a wide range of subfields such as computational pharmacology, computational genetics, computational bio-modeling, computational neuroscience, etc. The main goal of computational biology is to discover new biology and knowledge about living systems.


Some important Terms and Terminologies :

Database Schema and Instance: The overall structure of the database is called the database schema. For example, employee information in a company in a company database may be stored in relation to the following schema.
Employee ( Eid:string, Ename:string, Address:string, Salary:integer, Age:integer) Once created, the database schema is not expected to change frequently. Database administration is responsible for creating, deleting, and modifying database schema.

The collection of information stored in the database at a particular moment is called an instance of a database. It is the actual content of the database at a particular point in time.
Database instance changes frequently with every insertion, deletion, and update operations performed in data stored in a database.
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Unit-4 : The Internet (Notes of TU BSc. 4th Year Computer Science)

 The Internet
Syllabus: Definition; Internet Services (Electronic Mail, File Transfer, Telnet, Usenet News, and WWW); Uses of the Internet; Internet Address  


Internet is a global network providing a variety of information and communication facilities, consisting of interconnected networks using standardized communication protocols. The word internet comes from a combination between “interconnection” and “network”. The network is a collection of computers and devices connected via communication channels and transmission media allow to share resources (hardware, software, data, information). Generally, nobody owns the internet. Vinton Gray Cerf (also known as Vint Cerf) is the Father of the Internet.

Internet Services
The Internet allows us to access huge amounts of information such as text, graphics, sounds, and software across the world. Some of the internet services are Electronic Mail (E-mail), File Transfer, Telnet, Usenet News, and World Wide Web ( WWW).

  1. Electronic Mail: Electronic mail (E-mail) is used to send electronic messages over the internet. It provides services that allowed complex communication interaction. It provides the following facilities:
    - composing and sending/receiving a message.
    - Storing, forwarding, deleting, replying to a message.
    -Sending a single message to more than one person.
    -Sending text, voice, graphics, and videos.
  2. File Transfer: File transfer is the process of copying or moving a file from one computer to another over a network or Internet connection. It enables sharing, transferring, or transmitting a file or a logical data object between different users and/or computers both locally and remotely.
    A file transfer can be upload or download. File Transfer Protocol (FTP), Hypertext Transfer Protocol (HTTP), BitTorrent, and Simple File Transfer Protocol are the most common file transfer protocols used in computer networks and online.
    There are two main types of the file transfer:
    a) Pull-Based: The file transfer request is initiated by the receiver.
    b) Push Based: The file transfer request is initiated by the sender.
    Moreover, other than network or Internet, file transfer can be performed manually by copying a file to a new folder/drive in the same computer or by copying it on a USB pen drive, CD or other portable storage devices to be transferred to another computer.
  3. Telnet: It is used to log on to a remote computer that is attached to the internet. TELNET stands for Terminal Network. It is both TCP/IP applications. It provides direct access to various services on the Internet. Some of these services are available on your host, but Telnet is especially useful when these services are not available on your host.
  4. Usenet News/Newsgroup: It offers a forum for people to discuss topics of common interest. Usenet news service enables a group of internet users to exchange their views, ideas, information on some common topics of interest. Types of newsgroup a) moderated b) non-moderated
  5. World Wide Web (WWW): Commonly known as web, most popular internet service. It is a system of interlinked hypertext documents(called web pages) contained on the internet. A webpage contains text, graphics, animations, sounds, and videos.  All of the web pages maintained by an organization or individual are called a web site.  WWW uses Hypertext Transfer Protocol (HTTP) for fetching files on the internet. A web browser is a software application used to locate and display web pages. Some popular browsers are Microsoft Internet Explorer, Mozilla Firefox, Google Chrome, etc. Web server is a computer that delivers webpages. Every webpage on the internet has an address called Uniform Resource Locator (URL). URL is an addressing scheme used by web browsers to locate documents and other resources on the WWW.

Uses of the Internet
  • Online communication
  • Software sharing
  • Exchange of views on topics of common interest
  • Posting of information of general interest
  • Product promotion
  • Feedback about products
  • Customer support service
  • Online journals and magazines
  • Education and research
  • Entertainment
  • Exploring news and last technologies
  • Software downloading


Internet address
As we know, every device attached to the internet must be identified uniquely. For this, we need to provide an address to the devices attached to the internet. There are two types of addresses on the internet.
1) IP address
The numbered address provided to computers and other devices attached to the internet to identify them uniquely. Two versions of the internet protocol (IP) are in use, a) IP version 4 and b) IP version 6. Each version defines an IP address differently.
IP addresses can also be classified as Private IP addresses or Public IP addresses. An IP address that can be accessed over the internet is called a public IP address. A private IP address is any number or address assigned to a device on a private TCP/IP Local Area Network (LAN) that is accessible only within LAN.

2) Domain Name
As IP address are difficult to remember, domain names are named addresses provided to devices attached to the network. For example, www.fb.com is an example of a domain name.
Domain Name Server (DNS) helps to resolve the hostname to an address. It uses a hierarchical (tree) naming scheme and a distributed database of IP addresses and associated names.
A domain name is a symbolic string associated with an IP address. There are several domain names available. Some of them are generic such as .com, .edu, .gov, .net, etc. and some are country-level such as .np, .au, .in, .us, etc.



Some more Terms and Terminologies:

Information Retrieval Service: It involves browsing and information retrieval and provides customers the ability to find, view, download, and process information.

File Transfer Protocol (FTP): File Transfer Protocol is used to transfer files between computers over the network or the internet. It is commonly used to download a file from a server or to upload a file to a server by using the internet. FTP is an application protocol that uses the internet TCP/IP protocols. It includes many commands but only a few are used to retrieve files.

Protocol: Protocol is a set of guidelines or rules. A communication protocol is a formal description of message formats and the rules for exchanging those messages. A format that agreed to transfer data between two devices. Examples:
  1. Hypertext Transfer Protocol (HTTP)
  2. Internet Protocol (IP)
  3. Simple Mail Transfer Protocol (SMTP)
  4. Transmission Control Protocol (TCP)

Web Page: It is a document or resource of information that is suitable for the WWW and can be accessed through a web browser and displayed on a monitor or mobile device. This information is usually in HTML format and provides navigation to other webpages via hypertext links. It can contain texts, graphics, audio, video, and has built-in connections or links to other web documents.

Internet Protocol Address (IP address) is a 32 bits unique address that computing devices use to identify itself and communicate with other devices in the Internet Protocol network. There are 2 types of IP addresses. They are:
  1. Static IP address is an IP address that can be manually configured for a device and it will never change.
  2. Dynamic IP address is an IP address assigned by DHCP servers which can be changed automatically at any time.
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