Meta-evaluation of online and offline web search evaluation metrics

As in most information retrieval (IR) studies, evaluation plays an essential part in Web search research. Both offline and online evaluation metrics are adopted in measuring the performance of search engines. Offline metrics are usually based on relevance judgments of query-document pairs from assessors while online metrics exploit the user behavior data, such as clicks, collected from search engines to compare search algorithms. Although both types of IR evaluation metrics have achieved success, to what extent can they predict user satisfaction still remains under-investigated. To shed light on this research question, we meta-evaluate a series of existing online and offline metrics to study how well they infer actual search user satisfaction in different search scenarios. We find that both types of evaluation metrics significantly correlate with user satisfaction while they reflect satisfaction from different perspectives for different search tasks. Offline metrics better align with user satisfaction in homogeneous search (i.e. ten blue links) whereas online metrics outperform when vertical results are federated. Finally, we also propose to incorporate mouse hover information into existing online evaluation metrics, and empirically show that they better align with search user satisfaction than click-based online metrics

A Constant Fight between Id and Ego: Blanche’s Tragedy in A Streetcar Named Desire

Tennessee Williams famous play A Streetcar Named Desire showed readers the tragic downfall of a lady named Blanche DuBois, who falls from a respected school teacher to a frivolous socialite, and finally a “crazy” woman. This paper intends to interpret Blanche’s tragedy with Freudian theory of id/ego/superego, focusing on analyzing Blanche’s hidden id, and her struggle between the id and the ego under the influence of the social environment and in particular, the two man in her life, Stanley and Mitch.

Structural characterization of an α-1, 6-linked galactomannan from natural Cordyceps 2 sinensis

An α-1, 6-linked galactomannan was isolated and purified from natural Cordyceps sinensis. The fine structure analysis of this polysaccharide was elucidated based on partial acid hydrolysis, monosaccharide composition, methylation and 1D/2D nuclear magnetic resonance (NMR) spectroscopy. Monosaccharide composition analysis revealed that this polysaccharide was mainly composed of galactose (68.65%), glucose (6.65%) and mannose (24.02%). However, after partial acid hydrolysis the percentages of galactose, glucose and mannose were changed to 3.96%, 13.82% and 82.22%, respectively. The molecular weight of this polysaccharide was 7207. Methylation and NMR analysis revealed that this galactomannan had a highly branched structure, mainly consisted of a mannan skeleton and galactofuranosyl chains. The structure of galactofuranosyl part was formed by alternating (1 → 5)-lined β-Galf and (1 → 6)-liked β-Galf or a single (1 → 6)-liked β-Galf, attaching to the O-2 and O-4 of the mannose chain, and terminated at β-T-Galf. The mannan core was revealed by analyzing the partial acid hydrolysate of the galactomannan and the structure was composed of (1 → 6)-linked α-Manp backbone, with substituted at C-2 by short chains of 2-substituted Manp or Galf branches

Sources Fostering Academic Well-Being: Students\u27 Perspectives In A PBL Context

In a post-pandemic learning era, student academic well-being emerges to the attention of educational researchers. Referring to students’ thoughts and behaviors that contribute to doing well in an educational context and their academic life satisfaction, student academic well-being has a significant influence on their recruitment and retention, learning experience, academic achievement, and competence development. However, while academic well-being has been regarded as an important indicator of student persistence in their current study and learning outcomes, limited studies have explored engineering students’ academic well-being and other supportive factors in engineering education. While several studies have examined how well-being is constituted and how it can be measured from medical, mental health, and eudaimonic philosophical perspectives, understanding engineering student academic well-being from social-cognitive and sociocultural aspects is also important. This is because wellbeing is not only influenced by personal feelings and perceptions, but also dynamically framed by interpersonal relations, as well as contextual and institutional conditions. To increase retention and help engineering students to become agentic professionals, it is desirable to help them to become proactive and purposeful learners in their studies. Thus, aimed at filling in this literature gap, this study will adopt the Q methodology to explore how engineering students perceive the sources contributing to their academic well-being in a Danish university. Suggestions will be proposed to optimize future curriculum design to support student academic well-bein

Mechanical Design and Kinematic Modeling of a Cable-Driven Arm Exoskeleton Incorporating Inaccurate Human Limb Anthropomorphic Parameters

Compared with conventional exoskeletons with rigid links, cable-driven upper-limb exoskeletons are light weight and have simple structures. However, cable-driven exoskeletons rely heavily on the human skeletal system for support. Kinematic modeling and control thus becomes very challenging due to inaccurate anthropomorphic parameters and flexible attachments. In this paper, the mechanical design of a cable-driven arm rehabilitation exoskeleton is proposed to accommodate human limbs of different sizes and shapes. A novel arm cuff able to adapt to the contours of human upper limbs is designed. This has given rise to an exoskeleton which reduces the uncertainties caused by instabilities between the exoskeleton and the human arm. A kinematic model of the exoskeleton is further developed by considering the inaccuracies of human-arm skeleton kinematics and attachment errors of the exoskeleton. A parameter identification method is used to improve the accuracy of the kinematic model. The developed kinematic model is finally tested with a primary experiment with an exoskeleton prototype

Adaptive fuzzy sliding mode algorithm-based decentralised control for a permanent magnet spherical actuator

<p>The dynamic model of multi-degree-of-freedom permanent magnet (PM) spherical actuators is multivariate and nonlinear due to strong inter-axis couplings, which affects the trajectory tracking performance of the system. In this paper, a decentralised control strategy based on adaptive fuzzy sliding mode (AFSM) algorithm is developed for a PM spherical actuator to enhance its trajectory tracking performance. In this algorithm, the coupling terms are separated as subsystems from the entire system. The AFSM algorithm is applied in such a way that the fuzzy logic systems are used to approximate the subsystem with uncertainties. A sliding mode term is introduced to compensate for the effect of coupling terms and fuzzy approximation error. The stability of the proposed method is guaranteed by choosing the appropriate Lyapunov function. Both simulation and experimental results show that the proposed control algorithm can effectively handle various uncertainties and inter-axis couplings, and improve the trajectory tracking precision of the spherical actuator.</p

Further investigation on differential properties of the generalized Ness–Helleseth function

Let n be an odd positive integer, p be an odd prime with $p\equiv 3\pmod 4$, $d_{1} = {{p^{n}-1}\over {2}} -1$ and $d_{2} =p^{n}-2$. The function defined by $f_u(x)=ux^{d_{1}}+x^{d_{2}}$ is called the generalized Ness–Helleseth function over $\mathbb {F}_{p^n}$, where $u\in \mathbb {F}_{p^n}$. It was initially studied by Ness and Helleseth in the ternary case. In this paper, for $p^n \equiv 3 \pmod 4$ and $p^n \ge 7$, we provide the necessary and sufficient condition for $f_u(x)$ to be an APN function. In addition, for each u satisfying $\chi (u+1) = \chi (u-1)$, the differential spectrum of $f_u(x)$ is investigated, and it is expressed in terms of some quadratic character sums of cubic polynomials, where $\chi (\cdot )$ denotes the quadratic character of ${\mathbb {F}}_{p^n}$.acceptedVersio