1. Identify three benefits associated with the use of telecommunications technology.
2. What are the elements in a telecommunication system?
3. Compare and contrast the wireless communication channels.
4. Identify three telecommunications media that physically connect to telecommunication devices.
5. Define and describe three different services offered by telecommunication companies?
- Cost, time and distance?
- From a general model of telecommunications, there are 5 elements involved in moving the signal. The communication starts at the origin, a sending person (and computer), then goes through some telecommunications device, say a modem for example. Next the signal is transmitted through a medium, such as copper phone wires, to another telecommunications device, and finally a receiving computer – and hopefully a person too.
- Microwave, satellite, radio, cellular radio, and infrared:
Microwave towers transmit signal up to 30 miles – the curvature of Earth interrupts the line of sight at larger distances. Long distance telephone is a typical usage scenario for microwave as it is suited to high volume communications.
Satellite is replacing microwave as it reduces the 30 mile distance problem. Still using line of sight, but the footprint of a high altitude satellite is huge, overcoming the need for relay stations.
Radio-wave frequencies transmit over short distances and do not require relaying. Easy to install and inexpensive devices send radio waves through normal office walls, but can create electrical interference problems with other office equipment.
Cellular radio sounds like a localised low power relay antenna system for mobile telephone users and data communications. Computer processing coordinates the transmissions as mobile users move from one area to another.
Infrared light, not visible to the human eye, can be modulated or pulsed for conveying information. Your TV remote control uses IR and possibly peripherals communicating with your computer also utilise it.
- Coaxial cable, twisted-pair wire, and fiber-optic cable are three media which physically connect telecommunication devices.
- Services offered by telecommunications companies include:
- Switched lines are telephone lines provided by common carriers that people can access from their computers to transmit data to another computer. The transmission is routed or switched through paths to its destination.
- Integrated Services Digital Network [ISDN] is a high speed data transmission technology transferring voice, video, image and data simultaneously. ISDN uses existing telephone lines, and forms a popular upgrade for firms whose requirements exceed standard telephone capacity.
- Digital Subscriber Line [DSL] provides high speed digital data transmission from homes and businesses over existing telephone lines. A popular alternative to ISDN, and modems are necessary with DSL technology.
1. Define the term Database Management System.
2. Aware of the different components of a Database Management System.
3. Recognise the difference between logical and physical views of database data.
4. Define three database models and outline their basic features.
- A database management system (DBMS) is a program that provides access to all data in the database. It sits between all the programs and the stored data. A DBMS manages security and user access, maintains the integrity of stored data, and recovers information when the system fails. A range of tools provide users with the ability to perform functions such as maintain data, search, sort, display and print.
- Four components of a DBMS are:
- Data Model
- The data model defines the way data are conceptually structured. Examples include the hierarchical, network & relational models.
- Data Definition Language (DDL)
- A set of statements defining what types of information are in the database and how they will be structured, is known as the DDL. It acts as a link between between the logical and the physical views of the database. A DBMS user defines schemas and sub-schemas with the DDL. The schema is the logical description of the entire database and the listing of the data items and the relationships among them. A sub-schema is the specific set of data required by an application / user group.
- Data Manipulation Language (DML)
- To query the contents of the database, the DML is used. It allows users to retrieve, sort, display and delete the contents of a database.
- Data Dictionary
- Besides listing the standard data name and aliases for the element, the dictionary lists the names that reference this element in specific systems and identifies the individuals, business functions, applications, and reports that use the data element. Data dictionaries are advantageous for organisations in several ways including reduced data inconsistency, faster program development, and easier data modification.
- Users from all functional areas should assist in creating the logical design to ensure that their needs are identified and addressed. The logical design shows an abstract model of the data structures and arrangements to meet an organisations information needs. Identifying relationships among different data and grouping them is an integral part of developing the logical design.
Starting from the logical design, the physical design adds fine tuning for performance and cost considerations. For example, improved response time, reduced storage space, lower operating costs, etcetera.
- The structure of the relationships in most databases follow one of three models:
- Hierarchical – Early mainframe DBMS packages used a treelike structure. From the single root element, one can follow the branches of one-to-many relationships to reach the desired data element.
- Network – This model allows many-to-many relationships. Unlike the hierarchical model, the network model can access a data element by following one of several paths.
- Relational – Data elements are stored in simple tables, each record having a unique primary key. Inclusion of a foreign table’s primary key, a foreign key, can bind the relation.
A data model is a diagram of the data entities and their relationships. Data modelling usually involves understanding specific business problems and analysing the data and information to deliver a solution. With Entity-Relationship (ER) diagrams, individuals building a database have a blueprint to ensure relationships among data entities are correctly structured. ER diagrams also ensure that application programs are developed consistent with business operations and user needs.
1. Define the term database.
2. What is an attribute? How is it related to an entity?
3. What is data redundancy? Why is it a problem?
4. How would you describe the traditional approach to data management? How does it differ from the data base approach?
- An organised storage of logically related records could describe a database. This integrated collection of data is independent of application programs using the data.
- A data field represents an attribute [a characteristic or quality] of some entity [object, person, place, etc]. For example, an employee’s salary is an attribute that is a typical data field used to describe an entity who is an employee of a business. Thus an attribute is an identifiable part of the whole, that is the record.
- In a traditional approach to data management, data redundancy is among many of the problems. For example, a school will have student data in an enrolment fees file, in a class roll file, and a grades assessment file; all independently reproducing the same data. This repeated information is both a waste of storage space; and leads to inconsistent data, with no way of knowing which is correct.
- The traditional approach is not integrated. Every department of information has its own independent file, which often duplicates some of the data stored in other departments. The database approach integrates and rationalises the data into a centralised storage system. Data redundancy, data isolation (difficulty accessing data from different applications) and data inconsistency are minimised in a database approach. Additionally, data updates are easier because the data is stored in one accessible location. The drawbacks of a database management system (DBMS) include the cost of purchase and operation environment as well as any specialist staff required. If security is breached, more data is accessible to a trespasser. Also a failure in the DBMS will affect all application programs depending on it.
- How would you distinguish data and information? Information and Knowledge?
- Identify at least 6 characteristics of valuable information.
- What is a computer-based information system? What are its components?
Data are the raw facts. For example the grocery store manager’s list of every item sold today. Alone it is rather useless, trivial in fact. Comparing the actual total sales with the planned sales, gives added value and meaning, becoming information.
Knowledge is an awareness and understanding of a set of information, and ways that information can be made useful to support a specific task or reach a decision. (Stair and Reynolds, 2003)
Accuracy, completeness, economical, simplicity, timeliness, and flexibility are just 6 characteristics of valuable information.
An information system is a set of interrelated elements or components that collect [input], manipulate [process], and disseminate [output] data and information, and provide feedback mechanisms to meet an objective. (Stair and Reynolds, 2003) Thus a computer-based information system (CBIS) is one that inputs, processes, and outputs information using computer technologies. Components of a CBIS fall into groups of hardware, software, telecommunications, databases, people and procedures.
Stair, R.M., & Reynolds, G.W., (2003). Fundamentals of Information Systems, 2nd Edition.Thomson Learning.
- What is the Organisation?
- What are the Functional Areas?
- What are the Business Processes in 1 of the functional areas?
http://www.whitehorse.vic.gov.au/ takes us to the City of Whitehorse. There are 4 main functional areas: Corporate Services, City Development, Human Services, and Infrastructure. Business Processes within the Human Services area are: Community Development, Home & Community Care, Health & Family Services, and Arts & Recreation Development.