CIS 505 Discussions

profileCollegeman
cis505_w1_p2.ppt
Home>Information Systems homework help>CIS 505 Discussions

Communication
Technologies

CIS 505

Business Information

*

Welcome to Communication Technologies. In this lesson, we will discuss Business Information.

 

Next slide.

Topics

  • Audio
  • Data
  • Image
  • Video
  • Performance measures

*

The following topics will be covered in this lesson:

Audio;

Data;

Image;

Video; and

Performance measures.

Next slide.

Audio

  • Overview
  • Measured in bandwidth
  • Can be represented digitally
  • Applications
  • Human voice
  • Telephone
  • Telemarketing
  • Voice mail
  • Audio teleconferencing
  • Entertainment radio
  • Networking Implications
  • PBX
  • Centrex

*

The audio service supports applications based on sounds, usually of human voice. The primary application using audio service is telephone communication. Other applications include telemarketing, voice mail, audio teleconferencing, and entertainment radio. The quality of sound is characterized mainly by bandwidth. Audio information can also be represented digitally.

 

The most effective way of managing voice requirements is to tie all of the phones at a given site into a single system. There are two main alternatives for this:

 

The private branch exchange, and

Centrex.

 

The private bank exchange, or PBX, is an on-premise switching facility, owned or leased by an organization that interconnects the telephones within the facility and provides access to the public telephone system.

 

Centrex is a telephone company offering that provides the same sort of service as a PBX but performs the switching function in equipment located in the telephone company’s central office.

 

Either a PBX or Centrex facility can support a wide variety of voice-related services. Both voice mail and audio teleconferencing can be supported by either approach.

 

Next slide.

Overview

  • Examining Forms of Business Information
  • How impact is measured
  • Forms of business information
  • Types of services
  • Information Sources
  • Digital
  • Numerical
  • Text
  • Binary
  • Analog

*

It is important to understand how information communication relates to business requirements. A first step in this understanding is to examine the various forms of business information. Our examination covers the following topics:

 

How the impact of information sources on communications systems is measured,

 

The nature of the four major forms of business information,

 

The types of business services that relate to each of these forms of information, and

 

An introductory look at the implications of these services from the point of view of the communications requirements that they generate.

 

Information sources can produce information in digital or analog form. Digital information is presented as a sequence of discrete symbols from a finite alphabet. Examples are text, numerical data, and binary data.

 

Analog information is a continuous signal that can take on a continuum of values. An example is the electrical signal coming out of a microphone when someone speaks into it.

 

Next slide.

Data

  • Overview
  • Finite alphabet of symbols
  • Text
  • Numerical information
  • Character strings
  • Binary data
  • Using a database
  • Networking Implications

*

Data consists of information that can be represented by a finite alphabet of symbols, such as the digits zero through nine or the symbols represented on a terminal keyboard. Common examples of data include text and numerical information.

 

A familiar example of digital data is text or character strings. While textual data are most convenient for human beings, they cannot, in character form, be easily stored or transmitted by data processing and communications systems. Such systems are designed for binary data. Thus a number of codes have been devised by which characters are represented by a sequence of bits. Text, numerical data, and other types of data are typically organized into a database.

 

The networking requirements for supporting data applications in an organization vary widely.

 

Next slide.

Image

  • Image Representation
  • Vector
  • Raster
  • Gray scale image
  • Image and Document Formats
  • JPEG
  • GIF
  • PDF
  • Postscript
  • Networking Implications
  • Compression
  • Response time and throughput

*

The image service supports the communication of individual pictures, charts, or drawings. Image-based applications include facsimile, computer-aided design, publishing, and medical imaging.

 

There are a variety of techniques used to represent image formation. These fall into two main categories:

 

Vector graphics, and

Raster graphics.

 

With vector graphics, images are represented as a collection of straight and curved line segments. Vector graphics involve the use of binary codes to represent object type, size, and orientation.

 

With raster graphics, images are represented as a two-dimensional array of spots, called pixels.

 

A gray scale image is produced if each pixel is defined by more than one bit, representing shades of gray. Gray scale can also be used in vector graphics to define the gray scale of line segments or the interior of closed objects such as rectangles.

 

Images can also be defined in color. There are a number of schemes in use for this purpose. One example is RGB, which stands for red-green-blue, in which each pixel or image area is defined by three values, one for each of the three colors.

 

The most widely used format for raster-scan images is referred to as JPEG. The Joint Photographic Experts Group is a collaborative standards-making effort between ISO and ITU-T. The JPEG standard is designed to be general purpose, meeting a variety of needs such as desktop publishing, graphic arts, newspaper wire photo transmission, and medical imaging. JPEG is appropriate for high quality images.

 

Another format that is often seen on the Web is Graphics Interchange Format, or GIF. This is an eight-bit color format that can display up to two-hundred-fifty-six colors and is generally useful for non-photographic images.

 

There are also two popular document formats that are suitable for documents that include text and images. The Portable Document Format, or PDF, is widely used on the Web. Postscript is a page description language that is built into many desktop printers.

 

The various configurations by which image information is used and communicated do not fundamentally differ from the configurations used for text and numerical data.

 

The number of bits needed to represent an image can be reduced by the use of image compression techniques. Compression ratios of eight-to-sixteen bits are readily achieved.

 

Even with compression, the number of bits to be transmitted for image formation is large. As usual, there are two concerns:

 

Response time, and

Throughput.

 

Next slide.

Video

  • Overview
  • Sequence of pictures
  • Raster-scan images
  • Electron beam
  • Scanning process
  • Interlacing
  • Networking Implications
  • Television
  • Teleconferencing
  • Closed circuit TV
  • Multimedia

*

The video service carries sequences of pictures in time. In essence, video makes use of a sequence of raster-scan images. To produce a picture on the screen, an electron beam scans across the surface of the screen from left to right and top to bottom. At the end of the scan line, the beam is swept rapidly back to the left. When the beam reaches the bottom, it is swept rapidly back to the top. The beam is turned off during the retrace intervals.

 

To achieve adequate resolution, the beam produces a total of four-hundred-eighty three horizontal lines at a rate of thirty complete scans of the screen per-second. To provide a flicker free image without increasing the bandwidth requirement, a technique known as interlacing is used.

 

Applications based on video include instructional and entertainment television, teleconferencing, closed circuit TV, and multimedia.

 

Next slide.

Performance Measures

  • Response Times
  • System reaction to an input
  • Cost of better response time
  • Computer processing power
  • Competing requirements
  • User response time
  • System response time
  • Critical for transaction processing systems
  • Throughput
  • Increased capabilities
  • Demands of services

*

In the following section we will discuss two key parameters related to performance requirements:

 

Response time, and

Throughput.

 

Response time is the time it takes a system to react to a given input. In general, it is the time it takes for the system to respond to a request to perform a particular task.

 

Ideally, one would like the response time for any application to be short. However, it is almost always the case that shorter response time imposes greater cost. This cost comes from the following sources:

 

Computer processing power, and

Competing requirements.

 

Thus, the value of a given level of response time must be assessed versus the cost of achieving that response time.

 

Studies have shown that when a computer and a user interact at a pace that ensures that neither has to wait for the other, productivity increases significantly. The cost of work done on the computer drops, and quality tends to improve.

 

A transaction consists of a user command from a terminal and the system’s reply. It is the fundamental unit of work for only system users. It can be divided into two time sequences:

 

User response time, and

System response time.

 

In terms of types of computer-based information systems, rapid response time is most critical for transaction processing systems. The output of management information systems and decision support systems is generally a report or the results of some modeling exercise. In these cases, rapid turnaround is not essential.

 

The implication in terms of communications is this:

 

If there is a communications facility between an interactive user and the application and a rapid response time is required, then the communications system must be designed so that its contribution to delay is compatible with that requirement.

 

Another area where response time has become critical is the use of the World Wide Web, either over the Internet or over a corporate intranet. Response times can be gauged based on the level of user involvement in the session.

 

The trend toward higher and higher transmission speed makes possible increased support for different services that once seemed too demanding for digital communications. To make effective use of these new capabilities, it is essential to have a sense of the demands each service puts on the storage and communications of integrated information systems. Services can be grouped into data, audio, image, and video, whose demands vary greatly.

 

Next slide.

Summary

  • Audio
  • Data
  • Image
  • Video
  • Performance measures

*

We have now reached the end of this lesson. Let’s take a look at what we’ve covered.

 

We started the lecture off by examining that audio service supports applications based on sounds, usually of human voice. The primary application using audio service is telephone communication. Other applications include telemarketing, voice mail, audio teleconferencing, and entertainment radio. The quality of sound is characterized mainly by bandwidth. Audio information can also be represented digitally.

 

Next, we saw that data consists of information that can be represented by a finite alphabet of symbols, such as the digits zero through nine or the symbols represented on a terminal keyboard. Common examples of data include text and numerical information.

 

We then discussed that the image service supports the communication of individual pictures, charts, or drawings. Image-based applications include facsimile, computer-aided design, publishing, and medical imaging.

 

Lastly, we discovered that video service carries sequences of pictures in time. In essence, video makes use of a sequence of raster-scan images. To produce a picture on the screen, an electron beam scans across the surface of the screen from left to right and top to bottom.

 

This completes this lesson.