A three tier forensic model for automatic identification of evidence of child exploitation by analysing the content of chat-logs
- Authors: Miah, Md Waliur Rahman
- Date: 2016
- Type: Text , Thesis , PhD
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- Description: Detection of child exploitation (CE) in Internet chatting by locating evidence in the chat-log is an important issue for the protection of children from prospective online paedophiles. The un-grammatical and informal nature of chat-text makes it difficult for existing formal language processing techniques to handle the problem. The methodology of the current research avoids those difficulties by developing a multi-tier digital forensic model bulit on new ideas of psychological similarity measures and ways of applying them to chat-texts. The model uses text classifiers in the beginning to identify shallow evidence of CE. For locating the particular evidence it is required to identify the behavioural pattern of CE chats consisting of documented CE psychological stages and associate the perpetrators' posts to them. Similarities among the posts of a chat play an important role for the task of differentiating and identifying these stages. To accomplish this task a novel similarity measure is constructed backed by a dictionary with terms associated with each CE stage. Using the new similarity measure is constructed backed by a dictionary with terms associated with each CE stage. Using the new similarity measure in a hieraarchial agglomerative algoritm a new clusterer is built to cluster the posts of a chat-log into the CE stages to learn whether it follows the CE pattern. Inspired by the field of recognition of textual entailment a new soft entailment technique is developed and implemented to locate the specific posts associated with the CE stages. Those specific posts of the perpetrator are extarcted as the particular evidence from the chat-log. It is anticipated that the developed methodology will have many future pratical implementations. It would assist in the development of forensic tools for digital forensic experts in law and enforcement agencies to conveniently locate evidence of online child grooming in a confiscated hard disk drive. Another future implementation would be a parental filter used by parents to protect their children from potential online offenders.
- Description: Doctor of Philosphy
Constructing an inter-post similarity measure to differentiate the psychological stages in offensive chats
- Authors: Miah, Md Waliur Rahman , Yearwood, John , Kulkarni, Siddhivinayak
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of the Association for Information Science and Technology Vol. 66, no. 5 (2015), p. 1065-1081
- Full Text: false
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- Description: Offensive Internet chats, particularly the child-exploiting type, tend to follow a documented psychological behavioral pattern. Researchers have identified some important stages in this pattern. The psychological stages broadly include befriending, information exchange, grooming, and approach. Similarities among the posts of a chat play an important role in differentiating as well as in identifying these stages. In this article a novel similarity measure is constructed which gives high Inter-post-similarity among the chat-posts within a particular behavioral stage and low inter-post-similarity across different behavioral stages. A psychological stage corpus-based dictionary is constructed from mining the terms associated with each stage. The dictionary works as a background knowledge-base to support the similarity measure. To find the inter-post similarity a modified sentence similarity measure is used. The proposed measure gives improved recognition of inter-stage and intra-stage similarity among the chat posts compared with other types of similarity measures. The pairwise inter-post similarity is used for clustering chat-posts into the psychological stages. Results of experiments demonstrate that the new clustering method gives better results than some current clustering methods.
Detection of child exploiting chatsfrom a mixed chat dataset as a text classification task
- Authors: Yearwood, John , Miah, Md Waliur Rahman , Kulkarni, Siddhivinayak
- Date: 2011
- Type: Text , Conference paper
- Relation: Proceedings of Australasian Language Technology Association Workshop
- Full Text: false
- Reviewed:
- Description: There is a rapidly growing body of work in the use of Embodied Conversational Agents (ECA) to convey complex contextual relationships through verbal and non-verbal communication, in domains ranging from military C2 to e-learning. In these applications the subject matter expert in often naive to the technical requirements of ECAs. ENGAGE (the Extensible Natural Gesture Animation Generation Engine) is desgined to automatically generate appropriate and 'realistic' animation for ECAs based on the content provided to them. It employs syntactic analysis of the surface text and uses predefined behaviours for the ECA. We discuss the design of this system, its current applications and plans for its future development.