Posts Tagged ‘ALICE’

Improving Human-Like Qualities of Chatbots -Draft

Saturday, April 11th, 2009
This entry is part 4 of 13 in the series The State of Chatbots

Some researchers are designing chatbots with the intent of integrating more natural human-like interactions (De Angeli & Brahnam, 2008). Specifically, the developer may program certain responses that would sacrifice accuracy, but confer more human-like traits (Sing et al., 2006). For example, if a chatbot is presented with a math problem it could wait, as if to imitate thinking about the problem, or even give the wrong answer. This could be interpreted by the user as a human trait (failing or making a mistake), but in reality, it is a trick built into the programming. Researchers have attempted to add a sense of humor, through the use of self-contained jokes to their version of the chatbot ALICE (De Boni, Richardson, & Hurling, 2008). One could envision a scenario where a user would ask a question and the chatbot would reply: Jim, I’m not a machine, Im a doctor!”, I’m on my break, come back later.” or Are you sure you want me to check for this, I know its a waste of time”, which gives a jocular feel to the conversation.

Attempts to improve human-like characteristics include personality matching and relationship maintenance (De Boni et al., 2008; Abbatista, Degemmmis, Licchelli, Lops, Semeraro, & Zambetta, 2002). One researcher used shallow parsing and statistical natural language processing methods to change the style of interaction of their chatbot according to personality matching deboni08. For example, the chatbot could take on a submissive role when the user is portraying a dominate one. However, the authors found that users’ feelings were mixed about the chatbot using this style of interaction. Two different groups have developed chatbots that build upon previous interactions with the same user (De Boni et al., 2008; Abbatista et al., 2002). If a chatbot could incorporate the ability to recognize” a logged-in user and interact accordingly, the chatbot would be seen to be engaging in relationship maintenance (Abbatista et al., 2002). The chatbot would use a stored user profile and make recommendations in a proactive fashion (Abbatista et al., 2002). Both studies found that familiarity with a user did produce a more positive view of the chatbot’s interaction with that user.

Improving the chatbot’s ability to shift conversational topics is another approach to improving its human-like quality. Chat between humans is dynamic and a single utterance can become the focus of conversation (Montero – Enhancing computer). Another subsequent utterance (considered a catastrophe) may change the topic subject and the focus of the conversation would shift. One study attempted to model human chat by modeling relating utterances and changing topics more naturally (Montero & Araki, 2005). Based on ALICE, the chatbot database had categories to match patterns (user input and a template for chatbot reply). The authors programmed the chatbot to ask a question if it did not know a reply, trying to smoothly shift topic. Their methods included using a Data mining tool called KeyGraph to identify relationships between terms in a document, in particular, co-occurrence relationships of both high-probability and low-probability events. Utterances were broken down into words, visual results showed clusters of interrelated sentences, and links showed the shift in topics during chat. The researchers added critical categories by making the chatbot interject intelligent questions. Finally, they tested their chatbot’s performance by having one user interact with their chatbot, after which the user then gave an opinion of their conversation with the chatbot. Their results showed that the user rated the experience as better after adding the ability for the chatbot to shift topics. Although the study results were subjective, using this type of modeling could be a viable approach for a chatbot to control conversation flow.

Another attempt to add a proactive conversational element to a chatbot used a mixed-initiative interaction (L’Abbate et al., 2005). A mixed initiative refers to a exible interaction strategy where each participant can contribute to task what it does best. The agent can show initiative in conversation by introducing a change in conversationĀ  flow to improve believability. This approach was tested in Virtual Insurance Risk Management (VIRMA), an on-line risk management tool. Keeping with the rule-based approach, they were able to create user profiles and reduce the number of question and answer options. They tested the tool by having the users interact with the Risk Manager Online (RMO) user interface. From their results, the authors concluded that their approach enabled the conversations to be more domain specific, and improved the quality of the human-chatbot interaction.

Therefore, using approaches such as programming a chatbot to mimic human behavior like humor or shift conversations in certain situations, and adding conversation memory to the chatbot design, may confer more humanity to a chatbot. Perhaps combining a number of these tricks could increase the feeling of communicating with a human conversationalist.

Rule-Based Conversation -Draft

Saturday, April 11th, 2009
This entry is part 1 of 13 in the series The State of Chatbots

The majority of current chatbots use a rule-based approach to interact with the user. In order to imitate human conversations, developers use a linguistic model combined with computational algorithms to build chatbots. Depending on the chatbot, rules can be based on simple textual pattern matching or complicated rules based on inference mechanisms (De Angeli & Brahnam, 2008).

Chatbots analyze input and sends is to a dialog manager, which enables the chatbot to provide contextual information back to user. \Generally behind such dialog managers lies a complex-rich rule-based system.” (Gandhe & Traum, 2007). Chatbots view utterances as a sequence of tokens (divided up sentences) and methods are applied to these tokens such as random bot, nearest context, segmented-nearest context, and segmented-random. Random bot replies with a random utterance from a list of replies (Gandhe & Traum, 2007). Nearest context chatbots possess local coherence and so do not choose a random reply but choose a reply using a vector space model that has the nearest context to the current ongoing dialog. Segmented-nearest context chatbots try to use the broader context of the dialog as well as local coherence. Segmented-random chatbots use only global coherence so keeps coherence, but selects an utterance randomly that matches the context.

Pattern matching in chatbots means that they determine the most relevant keywords extracted from the last phrase inputted by the user and generate responses according to \if-then-else” rules (Zdravkova, 2000). Their ability can be enhanced by repeating slightly modiffed replies, and including statements that define the direction of the conversation with the user (Zdravkova, 2000).

AIML files contain the rules for chatbots (A.L.I.C.E. foundation website, 2009). The language AIML (first used with ALICE), is an extension of XML. AIML allows the use of categories and topics, and has iterative capabilities and logic functionality (Shawar et al., 2007). It consists of data objects made up of units called topics and categories. Categories are the lowest-level and are rules for pattern matching (user input and template to generate a response). Topics are optional and are a top-level unit with a related set of categories.

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  • RobertWhetsel.com is a BLOG by a computer scientist who works for a Think Tank specializing in Information Assurance planning and policy for the DoD. He is the founder of the Open Business Foundation, and the former CEO for RavenSong Open Technologies in Frederick, Maryland. E-mail him at rwhetsel@ravensong.com.
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