Meme Media and a Meme Pool

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Agent Media
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Three Different Meanings of Agents

• Software agents date back to the early days of AI
  work, to Carl Hewitts concurrent actor model.
• Since then, the word agent in computer science
  and software engineering has several different
  meanings.
• First it is used in the context of distributed AI
  systems and/or emergent computing systems.
• Each of these systems tries to model a complex
  intelligent system as a system of a large number
  of mutually communicating autonomous processing
  modules with much simpler capabilities.
• They call these modules collaborative agents, or
  simply agents.
• Collaborative agents emphasize autonomy and
  cooperation with other agents.

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• Agents in the context of human-computer
  interaction denote interface agents.
• They are computer generated virtual creatures
  that can interact with users in natural languages
  to help their access to various documents and
  applications.
• In 1987, Apple Computer has produced some
  videotape narrated by John Sculley, showing
  scenarios of how future versions of their
  personal computers would look.
• Their visionary system called Knowledge
  Navigator uses an intelligent agent in the
  interface.

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• The third definition stands for mobile agents.
• They are software modules that can travel through
  networks to interact with other modules at
  different sites.
• They partially execute themselves at different
  sites.
• Different from remote procedure calls that send
  messages to invoke some remote procedures
  residing at different sites and communicate with
  them, mobile agents send themselves to remote
  sites, execute their codes there to interact with
  other native objects there, and possibly return
  to their home sites.
• Mobile agents can deliver messages to distributed
  remote objects, and/or collect information from
  distributed remote objects.
• Studies on mobile agent systems developed their
  programming languages. Telescript from General
  Magic is the most famous one. Java is also used
  to program mobile agents, but it does not provide
  specific protocols for mobile agents.
• Mobile agents are increasing their significance
  especially in the context of electronic commerce.

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• The fourth definition stands for
  information/Internet agents.
• They perform the role of managing, manipulating,
  or collaborating information from many
  distributed sources, especially from those on
  WWW.
• They could be mobile. However, this is not the
  norm as yet.
• They are sometimes called Internet robots or
  Internet sofbots (software robots).

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• The fifth definition stands for reactive agents.
• Reactive agents represent special category of
  agents that do not process internal, symbolic
  models of their environments.
• Instead they respond in a stimulus-response
  manner to the present state of the environment in
  which they are embedded.

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• Other definitions stand for hybrid agents, and
  heterogeneous agent systems.
• Hybrid agents refer to those whose constitution
  is a combination of two or more agent
  philosophies within a singular agent, while
  heterogeneous agent systems refer to an
  integrated set-up of at least two or more agents
  that belong to two or more different agent
  classes.

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Mobile Agents and Pads

• Mobile agents travel through networks to visit
  various sites and to interact with objects there.
  
• Some return to their home sites, while others do
  not.
• Each mobile agent needs to have the capabilities
  to specify the followings, and to execute the
  specified mission
• Travel Course Which sites to visit in what
  order?
• Interaction Objects Which objects to interact
  with at each visited sites?
• Interaction Operation How to interact with
  each of them?

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• If mobile agents can interact with any objects at
  any sites through any operations, then even a
  network virus can be easily implemented as a
  mobile agent.
• We therefore need to introduce appropriate and
  reasonable restrictions on them.

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• Here we present an application framework of
  IntelligentPad for the implementation of mobile
  agents.
• In IntelligentPad, a mobile agent should be also
  a pad.
• Mobile agent pads need to dynamically interact
  with other pads.
• We assume that the interaction between a
  traveling agent pad and pads in each local site
  is coordinated by a special pad that is a priori
  installed at this local site under the agreement
  between the owner of the agent and the user of
  this local environment.
• This special pad is considered as an example of
  pad converters.

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• A pad converter is used with an InputPortPad and
  an OutputPortPad that are respectively connected
  to its input and output port slots.
• When a pad is dropped on the InputPortPad, it is
  input to the pad converter and processed there.
• For example, when an agent pad is dropped on the
  InputPortPad, it is absorbed, and the pad
  converter may make some local pads that are kept
  under its supervision communicate with this agent
  pad through accessing its special slot with set
  and gimme messages.
• After the completion of such communication, the
  same agent pad with a different state will be
  popped up on the OutputPortPad.
• The use of such a special kind of pad converters
  to coordinate the agents interaction at each
  destination site simplifies and standardizes the
  interaction of agent pads with local pads.

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• In this simplified framework for agent pads to
  interact with local pads, the local processing is
  governed by special pad converters, and not by
  agent pads.
• Agent pads are passively accessed through their
  special slots by these pad converters, and cannot
  actively access slots of any local pads.
• We can, of course, equally possibly propose
  different frameworks in which agent pads hold the
  initiative of the local processing.
• However, we intentionally propose this passive
  agent interaction with local pads for security
  reasons.
• Although the local pad holds the initiative of
  the interaction with agent pad, this interaction
  itself is invoked by the arrival of the agent
  pad.
• In this model, a special pad converter is a
  priori installed in each local system under the
  agreement of its owner.
• Agent pads cannot perform any operations in each
  local system other than those agreed by its owner.

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• The remaining problem we have to solve for agent
  pads is how to specify their travel courses.
• Since we use pad converters as local interaction
  objects, we can use meta pads of InputPortPads,
  OutputPortPads, and FlowDefinitionPads.
• Suppose that we want to make an agent pad to
  visit pad converters P(1), P(2), ..., P(n) in
  this order.
• Let MetaIn(i) and MetaOut(i) be meta pads for the
  InputPortPad and the OutputPortPad on P(i).
• The travel route of this agent pad is specified
  by FlowDefinitionPads that connect MetaOut(i) to
  MetaIn(i1) for each i.

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• These FlowDefinitionPads need to travel together
  with the agent pad.
• Furthermore, we want to activate the i-th
  FlowDefinitionPad that specifies a connection
  from MetaOut(i) to MetaIn(i1) only when the
  agent is visiting the pad converter P(i).
• Otherwise, whenever the agent visits a new site,
  each meta pad MetaOut(i) needs to inform its
  original output port pad of its new site address.
  
• This is necessary to keep the communication
  channel from each OutputPortPad to its meta pad.
  In order to avoid the unnecessary rewriting of
  site addresses, we need to activate MetaOut(i)
  only when it needs to be used.

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• Pads become active when they are loaded onto the
  desktop.
• Therefore, the agent pad needs to store all the
  FlowDefinitionPads as inactive pads in itself.
• While the agent pad is visiting the i-th pad
  converter, it only loads the i-th
  FlowDefinitionPad on itself as an active
  composite pad.
• For this purpose, we use a special pad called an
  IndexedPadManager that can store more than one
  composite pad.
• It indexes the stored pads in the order of their
  registration.
• When it receives an update message, this pad
  replaces its current child pad with its next
  stored pad.

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• The next figure shows an overall composition
  structure of an agent pad.
• The base pad has a function to issue an update
  message whenever it is put on an input port pad.
• The agent body is a pad that communicates with
  each pad converter.
• The IndexedPadManager holds FlowDefinitionPads.
• When visiting the i-th pad converter, only the
  i-th FlowDefinitionPad becomes active on the
  IndexedPadManager.
• After its interaction with local pads through the
  i-th pad converter, the agent pad pops up on
  MetaOut(i), which the i-th FlowDefinitionPad then
  sends to the next input meta pad MetaIn(i1).
• This transfers the agent pad to the next pad
  converter that may exist at different site.

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• The agent body may be a composite pad, which
  allows us to replace its components with other
  pads, and also to extend its function by pasting
  some other pads on it.
• Therefore, a whole agent pad is also re-editable,
  and its components are reusable.
• The client site of this agent pad can send it out
  by just dropping this pad onto the pad MetaIn(1),
  i.e., a meta pad of the InputPortPad connected to
  the inputPort slot of the first pad converter.
• The owner of each pad converter that coordinates
  the interaction between a traveling agent pad and
  pads in each local site can publish its meta pad
  together with the meta pads of IO port pads
  pasted on this pad converter through the Internet
  by embedding them in a web page.

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• The IntelligentPad approach to mobile agents has
  a large spectrum of application areas.
• Under the coordination of pad converters provided
  by destination sites, agent pads can interact
  with any types of local pads in each destination
  site they visit.
• These local pads might be data holding pads,
  multimedia document pads, application tools,
  database proxy pads, or proxy pads of industrial
  plant systems, computer-controlled devices, data
  acquisition systems, or transaction-based systems
  such as shipping and inventory management
  systems.
• Agent pads may only extract contents data from
  some local pads of these types, or they may
  acquire some local pads as they are.
• At each site it visits, an agent pad may further
  process what they acquire there.
• An agent pad may also process itself to change
  its state or its composition structure.

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• The use of mobile agent pads allows us to provide
  typical mobile agent applications with
  application frameworks that consist of component
  pads and generic pad composition structures.
• Each of these frameworks provides a construction
  kit including component pads and sample
  compositions for non-programmers to easily define
  the functions of both the mobile agents and the
  local pad converters.