Income tax evasion dynamics: Evidence from an agent-based econophysics model

We analyze income tax evasion dynamics in a standard model of statistical mechanics, the Ising model of ferromagnetism. However, in contrast to previous research, we use an inhomogeneous multi-dimensional Ising model where the local degrees of freedom (agents) are subject to a specific social temperature and coupled to external fields which govern their social behavior. This new modeling frame allows for analyzing large societies of four different and interacting agent types. As a second novelty, our model may reproduce results from agent-based models that incorporate standard Allingham and Sandmo tax evasion features as well as results from existing two-dimensional Ising based tax evasion models. We then use our model for analyzing income tax evasion dynamics under different enforcement scenarios and point to some policy implications. --tax evasion,tax compliance,Ising Model,econophysics,numerical simulation

A study of molecular order and motion in nematic liquid crystal mixtures

Materials which flow like fluids, but possess anisotropic properties like molecular crystals, are called \u27liquid crystals\u27. Studies of liquid crystals contribute to our understanding of how molecular orientation influences macroscopic properties. This thesis presents experimental and theoretical investigations of molecular order and dynamics in nematic liquid crystal systems. First, deuterium nuclear magnetic resonance is used to determine the degree of orientational order of both components of a liquid crystal mixture simultaneously. The temperature dependence of the four order parameters is interpreted using a newly developed mean field theory of nematic binary mixtures composed of biaxial molecules. Next, mean field theory is applied to predict the phase behavior of arbitrarily shaped nematogens. For single component liquid crystals, the four order parameters needed to quantify orientational order of biaxial molecules in a biaxial nematic phase are calculated as a function of temperature for both rod-like and plate-like liquid crystals. For binary mixtures, temperature-concentration phase diagrams for a variety of molecular shapes are calculated. These theoretical predictions suggest that binary mixtures of highly asymmetric molecules with opposite shape anisotrophies may display stable biaxial nematic phases. Last, deuterium nuclear magnetic spin relaxation rates are measured as a function of temperature to investigate the molecular motion of a liquid crystal and a liquid crystal binary mixture. These experimental results are interpreted using an anisotropic viscosity model of molecular reorientation. The temperature dependence of the correlation times for the molecular motions is examined and discussed. It is demonstrated that mixing probe molecules into a liquid crystal has a profound effect on the molecular motion of the liquid crystal

Cognitive Complexity of Heterosexual Arguments on the Civil Rights and Liberties of Homosexuals

This study examined how heterosexuals argue about the civil rights and liberties of homosexuals and how various factors interacted in determining how complex heterosexuals\u27 arguments are about two issues; the freedom of homosexuals to express their sexual orientation in public and the status of same-sex marriage. The factors examined were: value conflict (conflict in values experienced when dealing with an issue), issue familiarity (knowledge of the pros and cons of an issue), and perceived status (the perception that one\u27s views are shared by most people or by only a few). The value conflict experienced by the participants was assessed when participants rank ordered various values that were relevant to the two issues examined. Value conflict indices were obtained using a modified version of Tetlock\u27s (1986) Value Conflict Index. Perceived status and issue familiarity were measured using Likert scales. The latter two factors were obtained for each topic. Participants in the study orally expressed their arguments for and against the two issues. They defended their own stance and also criticized it. Likewise, they defended and criticized the opposing stance. The complexity of the arguments was assessed using a standardized scoring system developed by Baker-Brown, Ballard Bluck, deVries, Suedfeld, & Tetlock (1992) and Tetlock and Tyler (1996). Results indicate that an overwhelming majority of heterosexual participants thought that gays should have the freedom to discuss their sexuality in a public forum. However, the heterosexuals were ambivalent about the legalization of homosexual marriages. They argued in significantly more complex ways on this topic than on the previous one. Most of the participants felt their opinions were in the minority when dealing with free speech rights than when they were confronted with legalizing homosexual marriages. When arguing about the free speech rights of homosexuals, perceived status, value conflict, and issue familiarity were not predictive of argument complexity. However, on the issue of same-sex marriage, findings show that the influence of issue familiarity on complexity depended on value conflict. For those with little knowledge of the topic, it did not matter whether they were value conflicted or not. They argued at the same level of complexity. Value conflict, however, had an impact among those who were more familiar with the issue. Those who were familiar but had low value conflict were the most complex. Further results indicate that the impact of perceived status on complexity depended on issue familiarity. When participants were in the majority their levels of complexity did not vary according to how familiar they were with the topic. However, among those who believed their views were in the minority, they were more complex if they were less familiar with the topic. Results may be attributed to the fact that participants had definitive supportive opinions about homosexual free speech rights, but were conflicted about homosexual marriages. Individuals arguing about the rights issue were more certain about their stance and may have engaged in absolutist thinking. Furthermore, granting free speech to gays may simply not be a controversial issue for participants. Alternatively, the more complex arguments on the liberty issue may be attributed to the fact that heterosexuals were ambivalent about same sex marriage. They may have been struggling with the pros and cons of the issue. These complexity levels also may be due to motivational factors. Participants may have felt that the issue was irrelevant to them

Income Tax Evasion Dynamics: Evidence from an Agent-based Econophysics Model

We analyze income tax evasion dynamics in a standard model of statistical mechanics, the Ising model of ferromagnetism. However, in contrast to previous research, we use an inhomogeneous multi-dimensional Ising model where the local degrees of freedom (agents) are subject to a specific social temperature and coupled to external fields which govern their social behavior. This new modeling frame allows for analyzing large societies of four different and interacting agent types. As a second novelty, our model may reproduce results from agent-based models that incorporate standard Allingham and Sandmo tax evasion features as well as results from existing two-dimensional Ising based tax evasion models. We then use our model for analyzing income tax evasion dynamics under different enforcement scenarios and point to some policy implications.Comment: 24 pages, 8 figure

Interpretable Medical Image Classification using Prototype Learning and Privileged Information

Interpretability is often an essential requirement in medical imaging. Advanced deep learning methods are required to address this need for explainability and high performance. In this work, we investigate whether additional information available during the training process can be used to create an understandable and powerful model. We propose an innovative solution called Proto-Caps that leverages the benefits of capsule networks, prototype learning and the use of privileged information. Evaluating the proposed solution on the LIDC-IDRI dataset shows that it combines increased interpretability with above state-of-the-art prediction performance. Compared to the explainable baseline model, our method achieves more than 6 % higher accuracy in predicting both malignancy (93.0 %) and mean characteristic features of lung nodules. Simultaneously, the model provides case-based reasoning with prototype representations that allow visual validation of radiologist-defined attributes.Comment: MICCAI 2023 Medical Image Computing and Computer Assisted Interventio

Extracurricular Undergraduate Research: Student Perspectives and Experiences

This qualitative research examined the experiences and perspectives of undergraduate researchers to understand why they engaged in their research, what benefits they gained from the experience, and what challenges they faced in the conduct of their research