Search Results (327)

To achieve accurate 3D path tracking of a foot-wing hybrid-driven amphibious biomimetic robot under periodically varying forces, this study analyzes the periodic propulsion forces generated by the flapping motion of the robot’s feet and wings, along with the nonlinear hydrodynamic effects during underwater motion. To simplify the resulting complex force expressions, the scaling function averaging method is applied. Consequently, an accurate six-degree-of-freedom (6-DOF) dynamic model is established, in which the characteristic parameters of foot-wing flapping are adopted as control inputs. Based on this dynamic model, a nonlinear state-space representation of the robot’s underwater motion is constructed. In this formulation, 3D path tracking—derived from the Line-of-Sight (LOS) guidance method—and attitude stabilization are jointly defined as control objectives. To this end, a nonlinear model predictive control (NMPC) algorithm is employed to compute optimal control inputs, as it effectively addresses the challenges of strong nonlinearity, coupling effects, and multi-objective optimization. Finally, simulation experiments are conducted to validate the proposed control strategy. The results demonstrate that the robot is capable of accurately following the desired path. Furthermore, compared with conventional PID control, the NMPC approach significantly improves tracking stability and enhances the overall motion performance. Full article

The various definitions of academic freedom in the United States reflect the influence of social and political norms in its interpretation as both a professional and legal right. Yet, underlying these interpretations is the operational understanding, which includes both legal and professional considerations, that academic freedom is a widely recognized principle that grants professors the autonomy and authority to explore intellectual questions within their academic disciplines, conduct professional work, and express their views in the public sphere without undue interference or suppression. In other words, academic freedom is a foundational principle rooted in legal and institutional frameworks that safeguards professors’ ability to engage in intellectual inquiry, professional practice, and public discourse without undue interference. This principle extends beyond mere professional courtesy. It is recognized as essential to the functioning of higher education institutions and the broader democratic exchange of ideas. The public (including policymakers, industry leaders, media, and students) generally acknowledges academic freedom as an inherent protection that protects from unjustified interferences. By doing so, professors can participate in governance, disciplinary leadership, and extramural activities without the fear of retaliation or coercion. By insulating academic work from ideological, political, or economic constraints, academic freedom maintains the legitimacy and independence of scholarly inquiry in service to both knowledge advancement and the public good. Full article

Cyberhate presents a multifaceted, context-sensitive challenge that existing detection methods often struggle to tackle effectively. Large language models (LLMs) exhibit considerable potential for improving cyberhate detection due to their advanced contextual understanding. However, detection alone is insufficient; it is crucial for software to also promote healthier user behaviors and empower individuals to actively confront the spread of cyberhate. This study investigates whether integrating large language models (LLMs) with persuasive technology (PT) can effectively detect cyberhate and encourage prosocial user behavior in digital spaces. Through an empirical study, we examine users’ perceptions of a self-monitoring persuasive strategy designed to reduce cyberhate. Specifically, the study introduces the Comment Analysis Feature to limit cyberhate spread, utilizing a prompt-based fine-tuning approach combined with LLMs. By framing users’ comments within the relevant context of cyberhate, the feature classifies input as either cyberhate or non-cyberhate and generates context-aware alternative statements when necessary to encourage more positive communication. A case study evaluated its real-world performance, examining user comments, detection accuracy, and the impact of alternative statements on user engagement and perception. The findings indicate that while most of the users (83%) found the suggestions clear and helpful, some resisted them, either because they felt the changes were irrelevant or misaligned with their intended expression (15%) or because they perceived them as a form of censorship (36%). However, a substantial number of users (40%) believed the interventions enhanced their language and overall commenting tone, with 68% suggesting they could have a positive long-term impact on reducing cyberhate. These insights highlight the potential of combining LLMs and PT to promote healthier online discourse while underscoring the need to address user concerns regarding relevance, intent, and freedom of expression. Full article

This paper investigates the derivation of global shape functions in T-meshed quadrilateral patches through transfinite interpolation and local elimination. The same shape functions may be alternatively derived starting from a background tensor product of Lagrange polynomials and then imposing linear constraints. Based on the nodal points of the T-mesh, which are associated with the primary degrees of freedom (DOFs), all the other points of the background grid (i.e., the secondary DOFs) are interpolated along horizontal and vertical stations (isolines) of the tensor product, and thus, linear relationships are derived. By implementing these constraints into the original formula/expression, global shape functions, which are only associated with primary DOFs, are created. The quality of the elements is verified by the numerical solution of a typical potential problem of second order, with boundary conditions of Dirichlet and Neumann type. Full article

Based on the small perturbation method, the transient pressure control equation considering real gas effects was solved, and the fitting expression for the dynamic characteristic parameters of the gas film during the start-up process was obtained. Subsequently, the influence of structural parameters of spiral-groove dry-gas seals on the dynamic tracking of the stationary ring’s motion during the non-steady-state start-up process under three-degree-of-freedom perturbations was analyzed. The results show that when the stationary and rotating rings initially separate, the stationary ring exhibits good tracking performance for both axial and angular motions of the rotating ring, although the tracking capability varies significantly. As time and film thickness increase, the tracking capability gradually weakens, and for the working film thickness, the tracking parameters tend to stabilize when the working film thickness is reached. The larger the spiral angles and the deeper the dynamic pressure grooves, the poorer the axial and angular tracking performance of the sealing ring. The number of grooves has a minimal impact on the axial and angular tracking performance of the stationary ring. A higher balance coefficient improves the axial and angular tracking performance of the stationary ring. Full article

Background/Objectives: Self-care strategies enhance well-being and facilitate coping with emotional distress, particularly for palliative care professionals dealing with end-of-life issues. This study aimed to explore self-care practices among healthcare professionals working in palliative care settings by analyzing their perceptions and reflections. Methods: A total of 36 palliative care professionals participated in one of four focus group discussions on the topic of self-care. The discussions were transcribed and analyzed using qualitative content analysis. Results: Participants identified several self-care strategies as the most effective and the most frequently used, including lifestyle and emotional coping techniques. The meaning of self-care and its functions were delineated. Participants also identified factors that either facilitate or hinder self-care and discussed its impact on team well-being. Not all participants had received professional self-care training, and some struggled to identify their own strategies. However, participation in the focus group discussions was perceived as beneficial for improving work dynamics, group cohesion, communication, and freedom of expression. Conclusions: The positive feedback from the focus groups suggests that they are a valuable tool for fostering further discussions on self-care. The study recommends increasing the implementation of self-care strategies and professional training to enhance the well-being of palliative care professionals, their teams, and the patients they care for. Full article

Body posture dynamics have garnered significant attention in recent years due to their critical role in understanding the emotional states conveyed through human movements during social interactions. Emotions are typically expressed through facial expressions, voice, gait, posture, and overall body dynamics. Among these, body posture provides subtle yet essential cues about emotional states. However, predicting an individual’s gait and posture dynamics poses challenges, given the complexity of human body movement, which involves numerous degrees of freedom compared to facial expressions. Moreover, unlike static facial expressions, body dynamics are inherently fluid and continuously evolving. This paper presents an effective method for recognizing 17 micro-emotions by analyzing kinematic features from the GEMEP dataset using video-based motion capture. We specifically focus on upper body posture dynamics (skeleton points and angle), capturing movement patterns and their dynamic range over time. Our approach addresses the complexity of recognizing emotions from posture and gait by focusing on key elements of kinematic gesture analysis. The experimental results demonstrate the effectiveness of the proposed model, achieving a high accuracy rate of 91.48% for angle metric + DNN and 93.89% for distance + DNN on the GEMEP dataset using a deep neural network (DNN). These findings highlight the potential for our model to advance posture-based emotion recognition, particularly in applications where human body dynamics distance and angle are key indicators of emotional states. Full article

Statistical inference is used to estimate population parameters based on sample information and to quantify the sampling error based on the probability narrative. The population mean is inferred by its sample mean, but when using sample variance, the population variance is needed. In the quantitative analysis of the sampling error, the t-distribution is used. To determine the percentiles of the t-distribution, the cumulative probability density function is necessary. However, the analytic expression does not exist for the cumulative probability density function of the t-distribution. Its values are obtained using numerical integration. However, the percentiles of the t-distribution are not listed for degrees of freedom over 30, while only listed for every 10 data points in probability theory or mathematical statistics. This is inconvenient for research. Therefore, the cumulative probability density function of t-distribution was calculated using the Gaussian integration method in this study. The results show that the percentiles of the t-distribution are accurately estimated using the algorithm developed in this study. Full article

The legal and social perception of sexually motivated crimes has undergone profound transformations in the Czech lands from the Middle Ages to the present. Acts once considered grave moral transgressions, punishable by death, have been gradually decriminalised or even integrated into the realm of personal identity and cultural self-expression. This article examines the evolving legal frameworks and societal attitudes towards such offences, with a particular focus on their implications for family structures, inheritance rights, and genealogical continuity. By analysing historical judicial records—primarily early modern pitch books—alongside contemporary legislation, we highlight the shifting boundaries between crime, morality, and individual rights. Methodologically, this study combines a historical–legal analysis with comparative criminology to elucidate the changing regulatory mechanisms governing sexual behaviour. The findings illustrate that, while legal norms have progressively moved away from religious morality toward individual freedoms, some taboos persist, reflecting enduring social anxieties. The Czech case serves as a model for broader European trends, offering valuable insights into the interplay between law, social norms, and genealogical structures across different historical periods. Full article

To explore the nonlinear dynamics of a piezoelectric energy harvesting device, we consider the simultaneous parametric and external excitations. Based on Bernoulli–Euler beam theory, a new dynamic model is proposed taking into account the curvature of the beam, geometric and electro-mechanical coupling nonlinearities, and damping nonlinearity, with inextensible deformation. The system is discretized by using the Galerkin–Bubnov procedure and then is investigated by the optimal auxiliary functions method. Explicit analytical expressions of the approximate solutions are presented for a complex problem near the primary resonance. The main novelty of our approach relies on the presence of different auxiliary functions, the involvement of a few convergence-control parameters, the construction of the initial and first iteration, and much freedom in selecting the procedure for obtaining the optimal values of the convergence-control parameters. Our procedure proves to be very efficient, simple, easy to implement, and very accurate to solve a complicated nonlinear dynamical system. To study the stability of equilibrium points, the Routh–Hurwitz criterion is adopted. The Hopf and saddle node bifurcations are studied. Global stability is analyzed by the Lyapunov function, La Salle’s invariance principle, and Pontryagin’s principle with respect to the control variables. Full article

In the traditional three DOFs (degrees of freedom) PMs (parallel manipulators), the terminal constraints are constraint forces and torques. A recent study showed that the terminal constraints of some three DOFs PMs are screw-type constraints. However, determining the mobility of this class of PMs remains challenging. In order to solve the above problems, this paper discusses the mobility of PMs having independent screw-type terminal constraints by introducing the principal screws. Firstly, taking a 3-CCR (C: cylindrical joint, R: revolute joint) PM as an example, the problem of identifying the mobility of PMs having screw-type constraints is proposed. Secondly, combined with the analytical expression of the terminal constraint and theory of quadratic curve decomposition, the mobility determination approach is given. Finally, a numerical example for solving the principal screws and determining the mobility of the 3-CCR PM is provided. Furthermore, the axodes of four poses with three helical DOFs and four poses with three rotational DOFs were plotted. The results show that there is a special phenomenon in which three rotational DOFs and three helical DOFs exist alternately in the workspace of this PM. This paper provides a method for directly identifying the independent helical DOFs in parallel manipulators and for studying the distribution of helical DOFs within the workspace. Full article

In this work, we studied the main decomposition reactions on the ground state of nitromethane (CH₃NO₂) with the CASPT2 approach. The energetics of the main elementary reactions of the title molecule have been analyzed on the basis of Gibbs free energies obtained from standard expressions of statistical thermodynamics. In addition, we describe a mapping method (orthogonalized 3D representation) for the potential energy surfaces (PESs) by defining an orthonormal basis consisting of two $R^n$ orthonormal vectors (n, internal degrees of freedom) that allows us to obtain a set of ordered points in the plane (vector subspace) spanned by such a basis. Geometries and harmonic frequencies of all species and orthogonalized 3D representations of the PESs have been computed with the CASPT2 approach. It is found that all of the analyzed kinetically controlled reactions of nitromethane are endergonic. For such a class of reactions, the dissociation of nitromethane into CH₃ and NO₂ is the process with the lower activation energy barrier (ΔG); that is, the C-N bond cleavage is the most favorable process. In contrast, there exists a dynamically controlled process that evolves through a roaming reaction mechanism and is an exergonic reaction at high temperatures: CH₃NO₂ → [CH₃^…NO₂]* → [CH₃ONO]* → CH₃O + NO. The above assertions are supported by CASPT2 mappings of the potential energy surfaces (PESs) and classical trajectories obtained by “on-the fly” CASSCF molecular dynamics calculations. Full article

In the digital age, the rapid proliferation of misinformation and disinformation poses a critical challenge to societal trust and the integrity of public discourse. This study presents a comprehensive machine learning framework for fake news detection, integrating advanced natural language processing techniques and deep learning architectures. We rigorously evaluate a diverse set of detection models across multiple content types, including social media posts, news articles, and user-generated comments. Our approach systematically compares traditional machine learning classifiers (Naïve Bayes, SVMs, Random Forest) with state-of-the-art deep learning models, such as CNNs, LSTMs, and BERT, while incorporating optimized vectorization techniques, including TF-IDF, Word2Vec, and contextual embeddings. Through extensive experimentation across multiple datasets, our results demonstrate that BERT-based models consistently achieve superior performance, significantly improving detection accuracy in complex misinformation scenarios. Furthermore, we extend the evaluation beyond conventional accuracy metrics by incorporating the Matthews Correlation Coefficient (MCC) and Receiver Operating Characteristic–Area Under the Curve (ROC–AUC), ensuring a robust and interpretable assessment of model efficacy. Beyond technical advancements, we explore the ethical implications of automated misinformation detection, addressing concerns related to censorship, algorithmic bias, and the trade-off between content moderation and freedom of expression. This research not only advances the methodological landscape of fake news detection but also contributes to the broader discourse on safeguarding democratic values, media integrity, and responsible AI deployment in digital environments. Full article

The management of laicity in Mexico, legally and politically, is a federal issue that involves regulating the activities of Churches and religious communities in the public space, in their practices, rituals, and relations with the organs of the state. However, in recent years, the growing presence and activity of Churches at the local level has called into question the need to observe how laicity is managed by subnational governments, both state and municipal. Are there mechanisms at the local level to regulate the presence of religion in the public space? How are religious traditions presented as culturally managed? What are the demands of Churches on local authorities and what is their political relationship with them? How is the demand for religious freedom resolved locally without violating citizens’ other freedoms, such as the freedom of conscience in issues such as education, health, traffic, and freedom of expression? All this has put into perspective whether laicity and the secular state should continue to be a national dimension or whether it is necessary to rethink legal and political forms at the local level, building new frameworks of governance and governability. This text reviews the public management of laicity in eight entities of the country, which in turn is representative of the rest of the entities with their local variations. However, they generally move in the constant dimensions of religious diversity, interreligious councils, offices, or those in charge of religious affairs, and levels of municipal participation. The construction of a new laicity is then proposed, which does not exclude religion from the public agenda but rather a new secular perspective on the participation of religious communities in public affairs. From a Latin American perspective, Mexico is seen as an effective government regime that separates religion from politics, restricting the participation of religious organizations in the public agenda. However, at the local level, this regime is changing with the inclusion of faith-based organizations in politics. This will undoubtedly lead to a change in the historical concept, a reference point in the region. The term management of laicity refers to the regulation and administration of governments (services, legal support, spaces, and dialogues) with religious communities. Management (control, regulation, permits, sanctions, and recognition) is defined by law and in public policy towards religion from the federal government, but not in local governments that lack clear regulatory frameworks, intervention guidelines, and support, hence the emphasis on the term. Full article

This paper explores the complexities arising from the intersection of religious freedom and the principles of gender equality and non-discrimination, a pressing issue within the modern European landscape. It investigates these challenges by examining legal responses to religious speech linked to gender identity, particularly in cases categorized as hate speech under criminal law. Through an analysis of jurisprudence and relevant legal and institutional frameworks, the study highlights the risks of relying on criminal law to address such disputes, including potential misuse and overreach. It critically assesses the appropriateness and impact of criminal sanctions, noting their potential to deepen societal divisions and intensify polarization. Moving beyond punitive measures, the article advocates for alternative approaches to resolving these conflicts, emphasizing dialogue, mutual understanding, and respect as means to reduce tensions and build more inclusive communities. By integrating legal analysis with broader societal perspectives, this study makes a meaningful contribution to ongoing debates. It examines how fundamental rights can be effectively reconciled within pluralistic and democratic societies. Full article