Retrieving and classifying instances of source code plagiarism

Automatic detection of source code plagiarism is an important research field for both the commercial software industry and within the research community. Existing methods of plagiarism detection primarily involve exhaustive pairwise document comparison, which does not scale well for large software collections. To achieve scalability, we approach the problem from an information retrieval (IR) perspective. We retrieve a ranked list of candidate documents in response to a pseudo-query representation constructed from each source code document in the collection. The challenge in source code document retrieval is that the standard bag-of-words (BoW) representation model for such documents is likely to result in many false positives being retrieved, because of the use of identical programming language specific constructs and keywords. To address this problem, we make use of an abstract syntax tree (AST) representation of the source code documents. While the IR approach is efficient, it is essentially unsupervised in nature. To further improve its effectiveness, we apply a supervised classifier (pre-trained with features extracted from sample plagiarized source code pairs) on the top ranked retrieved documents. We report experiments on the SOCO-2014 dataset comprising 12K Java source files with almost 1M lines of code. Our experiments confirm that the AST based approach produces significantly better retrieval effectiveness than a standard BoW representation, i.e., the AST based approach is able to identify a higher number of plagiarized source code documents at top ranks in response to a query source code document. The supervised classifier, trained on features extracted from sample plagiarized source code pairs, is shown to effectively filter and thus further improve the ranked list of retrieved candidate plagiarized documents.     

The effect of network size on intra-network knowledge processes

This paper addresses a neglected topic in the knowledge management literature: how the size of a network of actors affects the nature of intra-network social relations and knowledge processes. It makes a theoretical contribution to developing understanding in this area drawing on a range of literatures including practice-based perspectives on knowledge, the literature on the embeddedness of social relations, and relevant knowledge management literature. The central focus of this paper is on the relationship between network size, network density, and how these variables affect intra-network knowledge processes. It suggests that as network size increases network density is likely to decrease (as it becomes problematic for the actors in such networks to retain strong ties with a significant proportion of the network's members), which it will be suggested has significant ramifications for intra-network knowledge processes. This paper concludes by reflecting on the implications of the ideas developed for network-based forms of organizing, and innovation processes.     

The development of source evaluation skills during adolescence: exploring different levels of source processing and their relationships (El desarrollo de las habilidades de evaluación de las fuentes durante la adolescencia: una exploración de los distintos niveles de procesamiento de las fuentes y sus relaciones)

Abstract

This study examines the development of source evaluation skills in four groups of students from 10 to 19 years of age. We designed a set of tasks based on a distinction between three components of source evaluation: the identification of source parameters; the evaluation of source features such as the source’s competence or benevolence under explicit instructions; and the use of source features in assessing a document’s relevance with respect to a given task. This inventory was administered to 245 teenagers in grades 5, 7 and 9 and to undergraduate students. All types of source evaluation skills developed throughout adolescence, with some of them remaining suboptimal for older readers. Furthermore, we found weak relationships between students’ identification of source parameters and their use of source features in the absence of any specific prompt. Finally, source evaluation tasks were weakly related to teenagers’ word reading skills. Taken together, these results document teenagers’ acquisition of source evaluation skills and warrant a distinction between readers’ ability to comprehend source features and to use these features when assessing information quality.     

Contents Volume 7 2001

Volume Contents

Contents Volume 7 2001     

Novice use of qualitative versus quantitative problem solving in electrostatics

Problem-solving behavior of six novice subjects attempting to solve an electrostatics problem in second-semester calculus-based college physics was observed and recorded. Five of the subjects were characterized as “A” or “B” students and one subject as a “D” student in introductory college physics. Although the A or B subjects were able to arrive at a “correct” solution to the problem, they exhibited major misconceptions about the problem situation as well as minimal qualitative understanding of the problem situation. The A or B subjects were successful in identifying, either from memory or written notes, equations relevant to electrostatics, whereas the D subject was not. The implication of this study is that current instruction in introductory calculus-based college physics and the students' previous science learnings place a premium on acquisition of correct quantitative solutions at the expense of qualitative understanding of physics problem situations.     

How shall i compare thee? Comparing the prudential value of actual virtual friendship

It has become commonplace to hold the view that virtual surrogates for the things that are good in life are inferior to their actual, authentic counterparts, including virtual education, virtual skill-demanding activities and virtual acts of creativity. Virtual friendship has also been argued to be inferior to traditional, embodied forms of friendship. Coupled with the view that virtual friendships threaten to replace actual ones, the conclusion is often made that we ought to concentrate our efforts on actual friendships rather than settle for virtual replacements. The purpose of this paper is to offer a balanced and empirically grounded analysis of the relative prudential value of actual and virtual friendship. That is, do actual and virtual friendships differ when it comes to enhancing our subjective well-being? In doing so, I will discuss a number of presuppositions that lie behind common criticisms of virtual friendship. This will include, among other considerations, their potential for replacing actual friendship, as well as the possibility for self-disclosure, trust, sharing and dynamic spread of happiness in virtual worlds. The purpose is not to arrive at a firm, normative conclusion, but rather to introduce a number of considerations that we should take into account in our individual deliberations over which role virtual friendships ought to have in our unique life situations.     

Data Mining to Combat Terrorism and the Roots of Privacy Concerns

Recently, there has been a heavy debate in the US about the government’s use of data mining in its fight against terrorism. Privacy concerns in fact led the Congress to terminate the funding of TIA, a program for advanced information technology to be used in the combat of terrorism. The arguments put forward in this debate, more specifically those found in the main report and minority report by the TAPAC established by the Secretary of Defense to examine the TIA issue, will be analysed to trace the deeper roots of this controversy. This analysis will in turn be used as a test case to examine the adequacy of the usual theoretical frameworks for these kinds of issues, in particular the notion of privacy. Whereas the dominant theoretical framing of the notion of privacy turns around access to information, most of the core arguments in the debate do not fit in this kind of framework. The basic disagreements in the controversy are not about mere access, they involve both access and use. Furthermore, whereas the issue of access by itself refers to a more or less static situation, the real disagreements much more concern the organisational dynamics of the use of information, the mechanisms in the organisation that control these dynamics, and the awareness present within the organisation of the ‘social risks’ these dynamics represent. The bottom line question is whether the assessment of these gives sufficient reason for trust.     

Japanese Conceptions of Privacy: An Intercultural Perspective

This paper deals with intercultural aspects of privacy, particularly with regard to important differences between Japanese and the Western views. This paper is based on our discussions with Rafael Capurro – a dialogue now represented by two separate but closely interrelated articles. The companion paper is broadly focused on the cultural and historical backgrounds of the concepts of privacy and individualism in “Western” worlds; our main theme focuses on different concepts of privacy in Japan and their sources in related aspects of Japanese culture. The interrelationship between our two papers is apparent in our taking up identical or similar topics in each paper. Reading our two papers in conjunction with each other will bring about deeper and broader insights into the diverse values and worldviews of Japan and Western cultures that underlie concepts of privacy that at a surface level appear to be similar     

Information visualisation: a holistic tool to discover knowledge. Case study – what video-telephone care? What elderly?

Today all parties within the health-care system demand more information and evidence to take more efficient and pinpointed management decisions. Their goal is a better patient and patient-care management. This paper presents an information visualisation approach to discover knowledge for the management of tele-home care for the elderly using the video-telephone: what type of elderly need what type of video-telephone interventions? This document focuses on the synthesis aspects of data mining with a view to knowledge discovery: the global, holistic, synthesis approach. More specifically, it summarises visually the relationships among the types of video-telephony care, among the segments of elderly, and between the types of interventions and the segments of elderly simultaneously. The graphical display allows delineating areas that group elderly with a similar/dissimilar video-telephony care profile. Information visualisation is a promising approach to provide insight into large multidimensional data sets. It fosters knowledge discovery.