Chatbots and task-oriented dialogue agents are evaluated on different metrics; chatbots are scored on how the user feels when interacting with the program, whereas task-oriented systems are scored based on their ability to complete a task.

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Dialogue systems, or conversational agents, are programs that communicate with users, through text and/or speech, in natural language.

Dialogue Systems

An on-going but a helpful book resource about NLP
https://web.stanford.edu/~jurafsky/slp3/

Speech and Language Processing (3rd ed. draft) 

1) Chatbots

2) Task-oriented dialogue agents

Types of Dialogue Systems

A Frame-based Dialogue System defines a dialogue frame structure and the formatted involved important components.

Frame-based Dialogue System

Language Generation is a sub-field of the field of Natural Language Processing (NLP), Artificial Intelligence (AI) and Cognitive Science (CS).

For natural language generation in the dialogue-state model, its task is to generate the text of the response to the user once a dialogue act has been decided. 

Natural Language Generation (NLG)

- Made use of by dialogue system.
- Represents the interactive function of the turn or sentence, combining the idea of speech acts and grounding into a single representation.
- Different types of dialogue systems require labeling different kinds of acts.

Dialogue Act

- Slot-filling, and the simpler tasks of domain and intent classification, are
special cases of the task of supervised semantic parsing,  in which we have a training set that associates each sentence with the correct set of slots, domain, and intent.
- A simple method is to train a sequence model to map from input word representation to slot fillers, domain, and intent.


Slots Filling

- Determines both the current state of the frame (the fillers of each slot), as well as the user’s most recent dialogue act.
- includes more than just the slot-fillers expressed in the current sentence:  the entire state of the frame at this point, summarizing all of the user’s constraints

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