Exercise 14

1. Spiders

A spider is an application that actively searches web pages and their links for search engines and other similar sites. Spiders collect information such as:

• Dead links
• Email addresses
• Web page titles, content etc.

Spiders are used by a majority, if not all, search engines on the web to add links in their databases for when people undertake a search. These applications are also commonly known as "bots" and "crawlers". Spiders have the ability to visit many sites in parallel, this is called the spiders "legs". In the case of deadlinks spiders can be used for maintenance tasks.

2. Software Agents

Intelligent - This type of agents have the ability of adaptation and the ability to learn. The ability to adapt allows the agent to sense the environment and reconfigure to meet. Algorithms and problem solving strategies can allow and agent to be able to adapt. The ability to learn can be established through trial and error which creates an illusion of behaviour.

Autonomous - Autonomous software agents claim to be autonomous through making independent decisions and taking action to meet the needs of an environment. These agents usually have the input of a user in order to make decisions within important applications.

Distributed - These agent can work together or be very loosely coupled, this allows them to be executed independently on distributed systems.

Multiagent Systems - Several agents can interact to form a multiagent system. Some agents may not have all data and methods inbuilt, this is when they may need to collaborate with other agents. These systems are also referred to as swarm systems and have their data is decentralized.

Mobile - These type of agents are able to move to other machines along with their data and execution state. These agents are used to backup files in client/server environments, monitoring network throughput and check resource utilization.

Fuzzy - "In computer science a fuzzy agent is a software agent that implements fuzzy logic. This software entity interacts with its environment through an adaptive rule-base and can therefore be considered as a type of intelligent agent." http://www.statemaster.com/encyclopedia/Fuzzy-agent

3. Software Agents in Use

Update Agents - These agents notify the user of when a change has occurred, eg:

• Alerting when news has been updated on a website
• Alerts a user when a job becomes available from a job board

Shopping Agents - These agents help with the purchasing of goods from retail websites. They can help find the best price for specific goods that the user is looking for.