Detecting Sockpuppets in Deceptive Opinion Spam

This paper explores the problem of sockpuppet detection in deceptive opinion spam using authorship attribution and verification approaches. Two methods are explored. The first is a feature subsampling scheme that uses the KL-Divergence on stylistic language models of an author to find discriminative features. The second is a transduction scheme, spy induction that leverages the diversity of authors in the unlabeled test set by sending a set of spies (positive samples) from the training set to retrieve hidden samples in the unlabeled test set using nearest and farthest neighbors. Experiments using ground truth sockpuppet data show the effectiveness of the proposed schemes.Comment: 18 pages, Accepted at CICLing 2017, 18th International Conference on Intelligent Text Processing and Computational Linguistic

Fundamental Approaches to Software Engineering

This open access book constitutes the proceedings of the 25th International Conference on Fundamental Approaches to Software Engineering, FASE 2022, which was held during April 4-5, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 17 regular papers presented in this volume were carefully reviewed and selected from 64 submissions. The proceedings also contain 3 contributions from the Test-Comp Competition. The papers deal with the foundations on which software engineering is built, including topics like software engineering as an engineering discipline, requirements engineering, software architectures, software quality, model-driven development, software processes, software evolution, AI-based software engineering, and the specification, design, and implementation of particular classes of systems, such as (self-)adaptive, collaborative, AI, embedded, distributed, mobile, pervasive, cyber-physical, or service-oriented applications

Vulnerability analysis of cyber-behavioral biometric authentication

Research on cyber-behavioral biometric authentication has traditionally assumed naïve (or zero-effort) impostors who make no attempt to generate sophisticated forgeries of biometric samples. Given the plethora of adversarial technologies on the Internet, it is questionable as to whether the zero-effort threat model provides a realistic estimate of how these authentication systems would perform in the wake of adversity. To better evaluate the efficiency of these authentication systems, there is need for research on algorithmic attacks which simulate the state-of-the-art threats. To tackle this problem, we took the case of keystroke and touch-based authentication and developed a new family of algorithmic attacks which leverage the intrinsic instability and variability exhibited by users\u27 behavioral biometric patterns. For both fixed-text (or password-based) keystroke and continuous touch-based authentication, we: 1) Used a wide range of pattern analysis and statistical techniques to examine large repositories of biometrics data for weaknesses that could be exploited by adversaries to break these systems, 2) Designed algorithmic attacks whose mechanisms hinge around the discovered weaknesses, and 3) Rigorously analyzed the impact of the attacks on the best verification algorithms in the respective research domains. When launched against three high performance password-based keystroke verification systems, our attacks increased the mean Equal Error Rates (EERs) of the systems by between 28.6% and 84.4% relative to the traditional zero-effort attack. For the touch-based authentication system, the attacks performed even better, as they increased the system\u27s mean EER by between 338.8% and 1535.6% depending on parameters such as the failure-to-enroll threshold and the type of touch gesture subjected to attack. For both keystroke and touch-based authentication, we found that there was a small proportion of users who saw considerably greater performance degradation than others as a result of the attack. There was also a sub-set of users who were completely immune to the attacks. Our work exposes a previously unexplored weakness of keystroke and touch-based authentication and opens the door to the design of behavioral biometric systems which are resistant to statistical attacks

Fundamental Approaches to Software Engineering

This open access book constitutes the proceedings of the 25th International Conference on Fundamental Approaches to Software Engineering, FASE 2022, which was held during April 4-5, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 17 regular papers presented in this volume were carefully reviewed and selected from 64 submissions. The proceedings also contain 3 contributions from the Test-Comp Competition. The papers deal with the foundations on which software engineering is built, including topics like software engineering as an engineering discipline, requirements engineering, software architectures, software quality, model-driven development, software processes, software evolution, AI-based software engineering, and the specification, design, and implementation of particular classes of systems, such as (self-)adaptive, collaborative, AI, embedded, distributed, mobile, pervasive, cyber-physical, or service-oriented applications

Sparse Fine-tuning for Inference Acceleration of Large Language Models

We consider the problem of accurate sparse fine-tuning of large language models (LLMs), that is, fine-tuning pretrained LLMs on specialized tasks, while inducing sparsity in their weights. On the accuracy side, we observe that standard loss-based fine-tuning may fail to recover accuracy, especially at high sparsities. To address this, we perform a detailed study of distillation-type losses, determining an L2-based distillation approach we term SquareHead which enables accurate recovery even at higher sparsities, across all model types. On the practical efficiency side, we show that sparse LLMs can be executed with speedups by taking advantage of sparsity, for both CPU and GPU runtimes. While the standard approach is to leverage sparsity for computational reduction, we observe that in the case of memory-bound LLMs sparsity can also be leveraged for reducing memory bandwidth. We exhibit end-to-end results showing speedups due to sparsity, while recovering accuracy, on T5 (language translation), Whisper (speech translation), and open GPT-type (MPT for text generation). For MPT text generation, we show for the first time that sparse fine-tuning can reach 75% sparsity without accuracy drops, provide notable end-to-end speedups for both CPU and GPU inference, and highlight that sparsity is also compatible with quantization approaches. Models and software for reproducing our results are provided in Section 6

What you see is what you feel:Top-down emotional effects in face detection

Face detection is an initial step of many social interactions involving a comparison between a visual input and a mental representation of faces, built from previous experience. Furthermore, whilst emotional state has been found to affect the way humans attend to faces, little research has explored the effects of emotions on the mental representation of faces. In four studies and a computational model, we investigated how emotions affect mental representations of faces and how facial representations could be used to transmit and communicate people’s emotional states. To this end, we used an adapted reverse correlation techniquesuggested by Gill et al. (2019) which was based on an earlier idea of the ‘Superstitious Approach’ (Gosselin & Schyns, 2003). In Experiment 1 we measured how naturally occurring anxiety and depression, caused by external factors, affected people’s mental representations of faces. In two sessions, on separate days, participants (coders) were presented with ‘colourful’ visual noise stimuli and asked to detect faces, which they were told were present. Based on the noise fragments that were identified by the coders as a face, we reconstructed the pictorial mental representation utilised by each participant in the identification process. Across coders, we found significant correlations between changes in the size of the mental representation of faces and changes in their level of depression. Our findings provide a preliminary insight about the way emotions affect appearance expectation of faces. To further understand whether the facial expressions of participants’ mental representations can reflect their emotional state, we conducted a validation study (Experiment 2) with a group of naïve participants (verifiers) who were asked to classify the reconstructed mental representations of faces by emotion. Thus, we assessed whether the mental representations communicate coders’ emotional states to others. The analysis showed no significant correlation between coders’ emotional states, depicted in their mental representation of faces and verifiers’ evaluation scores. In Experiment 3, we investigated how different induced moods, negative and positive, affected mental representation of faces. Coders underwent two different mood induction conditions during two separate sessions. They were presented with the same ‘colourful’ noise stimuli used in Experiment 1 and asked to detect faces. We were able to reconstruct pictorial mental representations of faces based on the identified fragments. The analysis showed a significant negative correlation between changes in coders’ mood along the dimension of arousal and changes in size of their mental representation of faces. Similar to Experiment 2, we conducted a validation study (Experiment 4) to investigate if coders’ mood could have been communicated to others through their mental representations of faces. Similarly, to Experiment 2, we found no correlation between coders’ mood, depicted in their mental representations of faces and verifiers’ evaluation of the intensity of transmitted emotional expression. Lastly, we tested a preliminary computational model (Experiment 5) to classify and predict coders’ emotional states based on their reconstructed mental representations of faces. In spite of the small number of training examples and the high dimensionality of the input, the model was successful just above chance level. Future studies should look at the possibility of improving the computational model by using a larger training set and testing other classifiers. Overall, the present work confirmed the presence of facial templates used during face detection. It provides an adapted version of a reverse correlation technique that can be used to access mental representation of faces, with a significant reduction in number of trials. Lastly, it provides evidence on how emotions can influence and affect the size of mental representations of faces

The advantage of being oneself: the role of applicant self-verification in organizational hiring decisions

In this paper, we explore whether individuals who strive to self-verify flourish or flounder on the job market. Using placement data from two very different field samples, we found that individuals rated by the organization as being in the top 10% of candidates were significantly more likely to receive a job offer if they have a strong drive to self-verify. A third study explored the mechanism behind this effect, using a quasi-experimental design to explore whether individuals who are high and low on this trait communicate differently in a structured mock job interview. Text analysis (LIWC) of interview transcripts revealed systematic differences in candidates’ language use as a function of their self-verification drives. These differences led an expert rater to perceive candidates with a strong drive to self-verify as less inauthentic and less misrepresentative than their low self-verifying peers, making her more likely to recommend these candidates for a job. Taken together, our results suggest that authentic self-presentation is an unidentified route to success on the job market, amplifying the chances that high-quality candidates can convert organizations’ positive evaluations into tangible job offers. We discuss implications for job applicants, organizations, and the labor market