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.     

Early Childhood Parenting Predicts Late Childhood Brain Functional Connectivity During Emotion Perception and Reward Processing

Seventy-nine 3-year olds and their mothers participated in a laboratory-based task to assess maternal hostility. Mothers also reported their behavioral regulation of their child. Seven years later, functional magnetic resonance imaging data were acquired while viewing emotional faces and completing a reward processing task. Maternal hostility predicted more negative amygdala connectivity during exposure to sad relative to neutral faces with frontal and parietal regions as well as more negative left ventral striatal connectivity during monetary gain relative to loss feedback with the right posterior orbital frontal cortex and right inferior frontal gyrus. In contrast, maternal regulation predicted enhanced cingulo-frontal connectivity during monetary gain relative to loss feedback. Results suggest parenting is associated with alterations in emotion and reward processing circuitry 7–8 years later.     

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.     

Literacies across sponsorscapes: mobilising notions of literacy sponsorship

Building from the concept ‘sponsors of literacy', the authors revisit three empirical studies to argue for mobilising notions of sponsorship beyond fixed conceptions of individual sponsors and literacy to lifewide perspectives that take into account sponsoring relations across the broader learning lives of youth. The authors take up the theoretical heuristic ‘sponsorscapes' as a lens for attending to the dynamically networked, reciprocal and human‐material dimensions of literacy practices. With cases drawn from across settings and research foci, including middle school students in a classroom setting, high school‐aged youth across contexts and a participant‐researcher's interactions with a college student, the authors argue that attending to sponsorscapes can contribute critical insight into the emergent, diverse and valued literacies and sponsorship thriving across lifewide learning pathways, while recognising learners' agentive roles in investing, resisting and sponsoring literacies.     

Contents Volume 7 2001

Volume Contents

Contents Volume 7 2001     

When ethnic minority students are judged as more suitable for the highest school track: a shifting standards experiment

When students are grouped into school tracks, this has lasting consequences for their learning and later careers. In Germany to date, some groups of students (boys, ethnic minority students) are underrepresented in the highest track. Stereotypes about these groups exist that entail negative expectations about their suitability for the highest track. Based on the shifting standards model, the present research examines if and how stereotypes influence tracking recommendations. According to this theory, members of negatively stereotyped groups will be judged more leniently or more strictly depending on the framing of the judgment situation (by inducing minimum or confirmatory standards). N = 280 teacher students participated in a vignette study in which they had to choose the amount of positive evidence for suitability they wanted to see before deciding to recommend a fictitious student to the highest track. A 2 (judgment standard: minimum vs. confirmatory) × 2 (target student’s gender: male vs. female) × 2 (target student’s ethnicity: no migration background vs. Turkish migration background) between-subjects design was used. No effects of target gender occurred, but the expected interaction of target’s ethnicity and judgment standard emerged. In the minimum standard condition, less evidence was required for the ethnic minority student to be recommended for the highest track compared to the majority student. In the confirmatory standards condition, however, participants tended to require less evidence for the ethnic majority student. Our experiment underlines the importance of the framing of the recommendation situation, resulting in a more lenient or stricter assessment of negatively stereotyped groups.