A study on plagiarism detection and plagiarism direction identification using natural language processing techniques

Ever since we entered the digital communication era, the ease of information sharing through the internet has encouraged online literature searching. With this comes the potential risk of a rise in academic misconduct and intellectual property theft. As concerns over plagiarism grow, more attention has been directed towards automatic plagiarism detection. This is a computational approach which assists humans in judging whether pieces of texts are plagiarised. However, most existing plagiarism detection approaches are limited to super cial, brute-force stringmatching techniques. If the text has undergone substantial semantic and syntactic changes, string-matching approaches do not perform well. In order to identify such changes, linguistic techniques which are able to perform a deeper analysis of the text are needed. To date, very limited research has been conducted on the topic of utilising linguistic techniques in plagiarism detection. This thesis provides novel perspectives on plagiarism detection and plagiarism direction identi cation tasks. The hypothesis is that original texts and rewritten texts exhibit signi cant but measurable di erences, and that these di erences can be captured through statistical and linguistic indicators. To investigate this hypothesis, four main research objectives are de ned. First, a novel framework for plagiarism detection is proposed. It involves the use of Natural Language Processing techniques, rather than only relying on the vii traditional string-matching approaches. The objective is to investigate and evaluate the in uence of text pre-processing, and statistical, shallow and deep linguistic techniques using a corpus-based approach. This is achieved by evaluating the techniques in two main experimental settings. Second, the role of machine learning in this novel framework is investigated. The objective is to determine whether the application of machine learning in the plagiarism detection task is helpful. This is achieved by comparing a thresholdsetting approach against a supervised machine learning classi er. Third, the prospect of applying the proposed framework in a large-scale scenario is explored. The objective is to investigate the scalability of the proposed framework and algorithms. This is achieved by experimenting with a large-scale corpus in three stages. The rst two stages are based on longer text lengths and the nal stage is based on segments of texts. Finally, the plagiarism direction identi cation problem is explored as supervised machine learning classi cation and ranking tasks. Statistical and linguistic features are investigated individually or in various combinations. The objective is to introduce a new perspective on the traditional brute-force pair-wise comparison of texts. Instead of comparing original texts against rewritten texts, features are drawn based on traits of texts to build a pattern for original and rewritten texts. Thus, the classi cation or ranking task is to t a piece of text into a pattern. The framework is tested by empirical experiments, and the results from initial experiments show that deep linguistic analysis contributes to solving the problems we address in this thesis. Further experiments show that combining shallow and viii deep techniques helps improve the classi cation of plagiarised texts by reducing the number of false negatives. In addition, the experiment on plagiarism direction detection shows that rewritten texts can be identi ed by statistical and linguistic traits. The conclusions of this study o er ideas for further research directions and potential applications to tackle the challenges that lie ahead in detecting text reuse.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Using Relational Schemata in a Computer Immune System to Detect Multiple-Packet Network Intrusions

Given the increasingly prominent cyber-based threat, there are substantial research and development efforts underway in network and host-based intrusion detection using single-packet traffic analysis. However, there is a noticeable lack of research and development in the intrusion detection realm with regard to attacks that span multiple packets. This leaves a conspicuous gap in intrusion detection capability because not all attacks can be found by examining single packets alone. Some attacks may only be detected by examining multiple network packets collectively, considering how they relate to the big picture, not how they are represented as individual packets. This research demonstrates a multiple-packet relational sensor in the context of a Computer Immune System (CIS) model to search for attacks that might otherwise go unnoticed via single-packet detection methods. Using relational schemata, multiple-packet CIS sensors define self based on equal, less than, and greater than relationships between fields of routine network packet headers. Attacks are then detected by examining how the relationships among attack packets may lay outside of the previously defined self

The Role of News Leaks in Governance and the Law of Journalists\u27 Confidentiality, 1795-2005

When the Supreme Court first grappled with prior restraints and the rights of reporters to attend criminal trials, it looked to history and the societal functions of the media in establishing presumptions that favored the press. This Article follows a similar path. Part II sketches the role of leaks in governance between the adoption of the Constitution and World War II to underscore the integral role leaks have played in the nation\u27s political communication. Part III shows that the general law of journalists\u27 confidentiality before and after Branzburg developed with little regard for the distinct institutional contributions of leaks. Part IV provides two perspectives on leaks that underscore their centrality in modern governance. When considered together, these perspectives suggest guidelines for courts as they weigh the value of different types of leaks. Finally, Part V recommends how the legal principles currently regulating journalists\u27 confidentiality can be adjusted slightly to accommodate the contributions of political leaks to governance