|
>What are they ? Possible uses Why use them ? The future Further resources |
What are they ?(Page 1 of 2)Intelligent agents are a relatively new direction for the development of software applications. Agent-based applications have been called 'the next significant breakthrough in software development'(Sargent, 1992), and 'the new revolution in software' (Ovum, 1994). Currently, agents are at the heart of many sub-fields of computer science and artificial intelligence. Agents are being used in numerous applications, ranging from comparatively small systems such as e-mail filters to large, open, complex, mission critical systems such as missile control systems. Any discussion should begin by introducing some basic concepts such as, perhaps most importantly, the notion of what an agent is. Unfortunately, we immediately run into difficulties, as there is a complete lack of any universally accepted definitions. "An agent is a software thing that knows how to do things that you could probably do yourself if you had the time." (quote from Ted Selker of the IBM Almaden Research Centre) We cannot come to a rock-solid formal definition of the concept "agent". Given the multiplicity of roles agents can play, this is quite impossible and even very impractical. Instead of a formal definition, a list of general characteristics of agents is given. Together these characteristics give a global impression of what an agent "is". The first group of characteristics are connected to the weak notion of the concept "agent". The fact that an agent should possess most, if not all of these characteristics, is something that most scientists have agreed upon at this moment. This is not the case, however, with the second group of characteristics, which are connected to the strong notion of the concept "agent". Perhaps the most general way in which the term agent is used, is to denote a hardware or (more usually) software-based computer system that enjoys the following properties: * autonomy : agents operate without the direct intervention of humans or others, and have some kind of control over their actions and internal state; * social ability : agents interact with other agents and (possibly) humans via some kind of agent communication language; * reactivity : agents perceive their environment (which may be the physical world, a user via a graphical user interface, a collection of other agents, the Internet, or perhaps all of these combined), and respond in a timely fashion to changes that occur in it. This may entail that an agent spends most of its time in a kind of sleep state from which it will awake if certain changes in its environment (like the arrival of new e-mail) give rise to it; * proactivity : agents do not simply act in response to their environment, they are able to exhibit goal-directed behaviour by taking the initiative; * temporal continuity : agents are continuously running processes (either running active in the foreground or sleeping/passive in the background), not once-only computations or scripts that map a single input to a single output and then terminate; * goal orientedness : an agent is capable of handling complex, high-level tasks. The decision how such a task is best split up in smaller sub-tasks, and in which order and in which way these sub-tasks should be best performed, should be made by the agent itself. For some researchers - particularly those working in the field of AI - the term agent has a stronger and more specific meaning than that sketched out in the previous section. These researchers generally mean an agent to be a computer system that, in addition to having the properties as they were previously identified, is either conceptualised or implemented using concepts that are more usually applied to humans. For example, it is quite common in AI to characterise an agent using mentalistic notions, such as knowledge, belief, intention, and obligation. Some AI researchers have gone further, and considered emotional agents. |
| Back to Main Menu | Next Page |
HOME PAGE | INTRODUCTION | WHAT IS AN AGENT| POSSIBLE USES |
| WHY USE AGENTS | THE FUTURE| FURTHER RESOURCES|
| REFERENCES |