bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phase oscillator optimization eliminates jittering during transition gaits in multimodal locomotion assisted by a portable hip exoskeleton
Authors: Yang Wei , Yan Zehao , Yu Linfan , Xu Linghui , Liu Xiaoguang , Yang Canjun 
Published: August 2023

AbstractTo be successfully used in daily life situations, exoskeletons should be effective across multimodal scenarios, including walking on various terrains, and transitions between locomotion modes such as walking-to-stop. Correct continuous gait phase estimation is essential for high-level walking assistance control. Despite the impressive advances in gait phase estimation for a variety of locomotion modes, transition gait phase estimation is rarely researched, leading to the jittering of exoskeletons during walking-to-stop transitions. We propose an optimized phase oscillator (PO-opt) that estimates the gait phase correctly during transition gaits in multimodal locomotion, which is beneficial to eliminating the jittering. In the phase plane, a lateral axis extreme difference (LAED) is adopted to classify transition gaits. The threshold of LAED for transition gaits in multimodal locomotion was preliminarily determined by simulation, which was then applied and validated in experiments. Simulation results indicated that a threshold of 15.0 was suitable for transition gaits classification during treadmill walking, free walking, and ramp ascent/descent, while results of the experiment showed that a threshold between 6.5 and 10.5 was applicable for treadmill walking, free walking, and stair ascent/descent. In particular, the jittering elimination rates for 3, 4, and 5 km/h treadmill walking were improved from 29%, 21%, and 4% (PO model) to 100%, respectively, when the threshold of LAED was set at 15.0 in PO-opt model. The results indicated a significant increase in the rate of jittering elimination when the PO-opt model was applied. The model holds great promise in real-world applications for prostheses and other types of exoskeletons.
Modeling of a two-degree-of-freedom fiber-reinforced soft pneumatic actuator
Authors: Ferrandy Varell , Indrawanto  , Ferryanto F. , Sugiharto Arif , Franco Enrico , Garriga-Casanovas Arnau , Mahyuddin Andi Isra , Rodriguez y Baena Ferdinando , Mihradi Sandro , Virdyawan Vani 
Published: August 2023

AbstractFiber winding reinforcement is widely used in soft robotic manipulators actuated by pressurized fluids. However, the specific effect of each type of winding on the bending motion of a tubular soft robotics manipulator with three chambers has not been explored widely. We present the development of precise finite element (FE) simulations and investigate the effect of helical fiber winding parameters on the bending motion of a two-degree-of-freedom manipulator with three internal chambers. We first show the development of an FE simulation that optimizes convergence and computational time and precisely matches the behavior of soft robots in practice. Compared to single-chamber robots, simulating three-chamber designs is more challenging due to the complex geometry. We then apply our FE model to simulate all the parameter variations. We show that for helical winding with a constant pitch, the closer the center of a chamber is to the intersection of the windings, the lower the bending stiffness of the chamber is. To minimize bending stiffness variation in different bending directions, the optimal angle between the center of the first chamber and the intersection of the two helical windings are 0° and 12°. Reducing the pitch of the helical windings or using other types of windings (i.e., ring winding or six helical winding) reduces the stiffness variation across different bending directions. The FE simulations are compared with experiments showing that the model can capture complex bending behaviors of the manipulator, even though the estimation tends to be less accurate at higher bending angles.
Equidistribution of exponential sums indexed by a subgroup of fixed cardinality
Authors: UNTRAU THÉO 
Published: August 2023

AbstractWe consider families of exponential sums indexed by a subgroup of invertible classes modulo some prime power q. For fixed d, we restrict to moduli q so that there is a unique subgroup of invertible classes modulo q of order d. We study distribution properties of these families of sums as q grows and we establish equidistribution results in some regions of the complex plane which are described as the image of a multi-dimensional torus via an explicit Laurent polynomial. In some cases, the region of equidistribution can be interpreted as the one delimited by a hypocycloid, or as a Minkowski sum of such regions.
L’apport des données participatives pour l’étude linguistique des français du monde : le cas de l’opposition /a∼ɑ/
Authors: Hutin Mathilde , Allassonnière-Tang Marc 
Published: August 2023

RÉSUMÉLe français est une langue parlée par plusieurs centaines de millions de locuteurs en Europe, en Afrique et en Amérique. Une telle dispersion favorise la variation, mais de grands corpus unifiés permettant de rendre compte de cette variation à l’échelle mondiale restent rares, et dans tous les cas nécessitent des efforts financiers et humains non négligeables, à l’instar du projet de Phonologie du Français Contemporain. Dans cet article, nous présentons une alternative possible : les données participatives. Pour ce faire, nous présentons Lingua Libre, la médiathèque linguistique participative de Wikimédia France, et l’utilisons pour décrire la variation sur une opposition phonémique entre deux voyelles ouvertes, /a/ et /ɑ/, dans de nombreuses variétés de français. Les données de 38 locuteurs provenant de 26 points d’enquête sont traitées automatiquement et comparées aux mesures présentées dans la littérature passée. Les résultats montrent que la plateforme a le potentiel de donner des résultats conformes à ceux des études de terrain professionnelles. L’article conclut sur les avantages et les limites de la plateforme, tout en proposant des pistes d’amélioration.
Implementing Backjumping by Means of Exception Handling
Authors: DRABENT WŁODZIMIERZ 
Published: August 2023

AbstractWe discuss how to implement backjumping (or intelligent backtracking) in Prolog by using the built-ins throw/1 and catch/3. We show that it is impossible in a general case, contrary to a claim that “backjumping is exception handling." We provide two solutions. One works for binary programs; in a general case it imposes a restriction on where backjumping may originate. The other restricts the class of backjump targets. We also discuss implementing backjumping by using backtracking and the Prolog database. Additionally, we explain the semantics of Prolog exception handling in the presence of coroutining.
Dyadic Existential Rules
Authors: GOTTLOB GEORG , MANNA MARCO , MARTE CINZIA 
Published: August 2023

AbstractExistential rules form an expressive
${{\textsf{Datalog}}}$
-based language to specify ontological knowledge. The presence of existential quantification in rule-heads, however, makes the main reasoning tasks undecidable. To overcome this limitation, in the last two decades, a number of classes of existential rules guaranteeing the decidability of query answering have been proposed. Unfortunately, only some of these classes fully encompass
${{\textsf{Datalog}}}$
and, often, this comes at the price of higher computational complexity. Moreover, expressive classes are typically unable to exploit tools developed for classes exhibiting lower expressiveness. To mitigate these shortcomings, this paper introduces a novel general syntactic condition that allows us to define, systematically and in a uniform way, from any decidable class
$\mathcal{C}$
of existential rules, a new class called
${{\textsf{Dyadic-}\mathcal{C}}}$
enjoying the following properties: (i) it is decidable; (ii) it generalizes
${{\textsf{Datalog}}}$
; (iii) it generalizes
$\mathcal{C}$
; (iv) it can effectively exploit any reasoner for query answering over
$\mathcal{C}$
; and (v) its computational complexity does not exceed the highest between the one of
$\mathcal{C}$
and the one of
${{\textsf{Datalog}}}$
.
Detection and treatment of outliers for multivariate robust loss reserving
Authors: Avanzi Benjamin , Lavender Mark , Taylor Greg , Wong Bernard 
Published: August 2023

AbstractTraditional techniques for calculating outstanding claim liabilities such as the chain-ladder are notoriously at risk of being distorted by outliers in past claims data. Unfortunately, the literature in robust methods of reserving is scant, with notable exceptions such as Verdonck & Debruyne (2011,Insurance: Mathematics and Economics,48, 85–98) and Verdonck & Van Wouwe (2011,Insurance: Mathematics and Economics,49, 188–193). In this paper, we put forward two alternative robust bivariate chain-ladder techniques to extend the approach of Verdonck & Van Wouwe (2011,Insurance: Mathematics and Economics,49, 188–193). The first technique is based on Adjusted Outlyingness (Hubert & Van der Veeken, 2008.Journal of Chemometrics,22, 235–246) and explicitly incorporates skewness into the analysis while providing a unique measure of outlyingness for each observation. The second technique is based onbagdistance(Hubertet al., 2016.Statistics: Methodology, 1–23) which is derived from the bagplot; however; it is able to provide a unique measure of outlyingness and a means to adjust outlying observations based on this measure.Furthermore, we extend our robust bivariate chain-ladder approach to an N-dimensional framework. The implementation of the methods, especially beyond bivariate, is not trivial. This is illustrated on a trivariate data set from Australian general insurers and results under the different outlier detection and treatment mechanisms are compared.
Spectral Characteristics of Phase Fluctuations at High Latitude
Authors: Song K. , Hamza A. M. , Jayachandran P. T. , Meziane K. , Kashcheyev A. 
Published: August 2023

AbstractIt has long been established that ionospheric electron density irregularities cause random rapid amplitude and phase fluctuations in trans‐ionospheric radio signals. Various types of ground‐based measurements, including radar and Global Navigation Satellite System (GNSS) receivers, have been utilized to gain insights into the plasma mechanisms that could lead to the development of these ionospheric irregularities. The spectral characteristics of radio wave signals emitted by GNSSs and detected by the Canadian High Arctic Ionospheric Network Global Positioning System (GPS) receivers are analyzed to try and identify the spectral signatures of the ionospheric plasma irregularities. In the polar region, we have confirmed that phase fluctuations in the GPS signal are not always accompanied by amplitude fluctuations. For the first time, a systematic comparison is conducted on the spectral properties of phase‐fluctuation events in the absence and presence of amplitude scintillations, respectively. More specifically, a spectral characterization is performed on 41 events recorded by three receivers positioned within the auroral oval. When fluctuations above the background level are solely observed in the signal's phase, the spectrum of phase variations exhibits a consistent steepness. Conversely, the presence of amplitude scintillation is accompanied by an increase in power at higher frequencies, resulting in shallower spectra. This analysis provides yet another physical element suggesting that the rapid fluctuations observed in the signal's amplitude may be caused by Fresnel‐scale irregularities arising from a gradient‐drift‐like instability while the phase variations seem to be consistent with a refractive mechanism caused by large‐scale ionospheric structures.
The Choice of Baseline Period Influences the Assessments of the Outcomes of Stratospheric Aerosol Injection
Authors: Visioni D. , Bednarz E. M. , MacMartin D. G. , Kravitz B. , Goddard P. B. 
Published: August 2023

AbstractThe specifics of the simulated injection choices in the case of stratospheric aerosol injections (SAI) are part of the crucial context necessary for meaningfully discussing the impacts that a deployment of SAI would have on the planet. One of the main choices is the desired amount of cooling that the injections are aiming to achieve. Previous SAI simulations have usually either simulated a fixed amount of injection, resulting in a fixed amount of warming being offset, or have specified one target temperature, so that the amount of cooling is only dependent on the underlying trajectory of greenhouse gases. Here, we use three sets of SAI simulations achieving different amounts of global mean surface cooling while following a middle‐of‐the‐road greenhouse gas emission trajectory: one SAI scenario maintains temperatures at 1.5°C above preindustrial levels (PI), and two other scenarios which achieve additional cooling to 1.0°C and 0.5°C above PI. We demonstrate that various surface impacts scale proportionally with respect to the amount of cooling, such as global mean precipitation changes, changes to the Atlantic Meridional Overturning Circulation and to the Walker Cell. We also highlight the importance of the choice of the baseline period when comparing the SAI responses to one another and to the greenhouse gas emission pathway. This analysis leads to policy‐relevant discussions around the concept of a reference period altogether, and to what constitutes a relevant, or significant, change produced by SAI.
Seasonal Variability of the Surface Ocean Carbon Cycle: A Synthesis
Authors: Rodgers Keith B. , Schwinger Jörg , Fassbender Andrea J. , Landschützer Peter , Yamaguchi Ryohei , Frenzel Hartmut , Stein Karl , Müller Jens Daniel , Goris Nadine , Sharma Sahil , Bushinsky Seth , Chau Thi‐Tuyet‐Trang , Gehlen Marion , Gallego M. Angeles , Gloege Lucas , Gregor Luke , Gruber Nicolas , Hauck Judith , Iida Yosuke , Ishii Masao , Keppler Lydia , Kim Ji‐Eun , Schlunegger Sarah , Tjiputra Jerry , Toyama Katsuya , Vaittinada Ayar Pradeebane , Velo Antón 
Published: August 2023

AbstractThe seasonal cycle is the dominant mode of variability in the air‐sea CO2 flux in most regions of the global ocean, yet discrepancies between different seasonality estimates are rather large. As part of the Regional Carbon Cycle Assessment and Processes Phase 2 project (RECCAP2), we synthesize surface ocean pCO2 and air‐sea CO2 flux seasonality from models and observation‐based estimates, focusing on both a present‐day climatology and decadal changes between the 1980s and 2010s. Four main findings emerge: First, global ocean biogeochemistry models (GOBMs) and observation‐based estimates (pCO2 products) of surface pCO2 seasonality disagree in amplitude and phase, primarily due to discrepancies in the seasonal variability in surface DIC. Second, the seasonal cycle in pCO2 has increased in amplitude over the last three decades in both pCO2 products and GOBMs. Third, decadal increases in pCO2 seasonal cycle amplitudes in subtropical biomes for both pCO2 products and GOBMs are driven by increasing DIC concentrations stemming from the uptake of anthropogenic CO2 (Cant). In subpolar and Southern Ocean biomes, however, the seasonality change for GOBMs is dominated by Cant invasion, whereas for pCO2 products an indeterminate combination of Cant invasion and climate change modulates the changes. Fourth, biome‐aggregated decadal changes in the amplitude of pCO2 seasonal variability are largely detectable against both mapping uncertainty (reducible) and natural variability uncertainty (irreducible), but not at the gridpoint scale over much of the northern subpolar oceans and over the Southern Ocean, underscoring the importance of sustained high‐quality seasonally resolved measurements over these regions.
The Effect of Initial Vortex Asymmetric Structure on Tropical Cyclone Intensity Change in Response to an Imposed Environmental Vertical Wind Shear
Authors: Gao Qi , Wang Yuqing 
Published: August 2023

AbstractPrevious studies have investigated how the environmental vertical wind shear (VWS) may trigger the asymmetric structure in an initially axisymmetric tropical cyclone (TC) vortex and how TC intensity changes in response. In this study, the possible effect of the initial vortex asymmetric structure on the TC intensity change in response to an imposed environmental VWS is investigated based on idealized full‐physics model simulations. Results show that the effect of the asymmetric structure in the initial TC vortex can either enhance or suppress the initial weakening of the TC in response to the imposed environmental VWS. When the initial asymmetric structure is in phase of the VWS‐induced asymmetric structure, the TC weakening will be enhanced and vice versa. Our finding calls for realistic representation of initial TC asymmetric structure in numerical weather prediction models and observations to better resolve the asymmetric structure in TCs.
Thermally Direct Mesoscale Circulations Caused by Land Surface Roughness Anomalies
Authors: Cheng Yu , McColl Kaighin A. 
Published: August 2023

AbstractDeforestation, urbanization and construction of wind farms can change the land surface roughness, which can further influence surface heat fluxes and thus weather and climate. Land surface roughness anomalies can dynamically trigger convergence through changing mean wind speed. Here, we report a new mechanism, in which roughness anomalies cause thermally direct mesoscale circulations and anomalous precipitation. To study this mechanism, we conduct cloud‐permitting simulations over an idealized land surface with prescribed surface roughness anomalies. Anomalously high roughness increases turbulent mixing near the surface, which decreases land surface temperature and outgoing longwave radiation. The additional surface net radiation partly goes into greater sensible heat flux, which triggers mesoscale circulations driven by differential heating. As a result, precipitation over the high‐roughness anomaly is generally larger than that over the low‐roughness background. This new mechanism, not present in climate models, may be relevant to storm formation over wind farms, cities and forests.
An Exact Solution to the Linearized Richards Equation for Layered Media With Flexible Initial Condition
Authors: Chen Zhang‐Long , Huang Yiyi , Fang Hongwei , Yeh Tian‐Chyi Jim , Zha Yuanyuan 
Published: August 2023

AbstractSrivastava and Yeh (1991, https://doi.org/10.1029/90WR02772) derived an exact solution to the linearized Richards equation (LRE) for two‐layer medium infiltration using the Laplace transform (LT) method with a particular initial condition assumed, making the most pioneering contribution to the derivation of exact solutions to the layered‐medium LRE (i.e., ES‐LMLREs). However, the LT method is unsuitable for deriving an ES‐LMLRE that considers either an arbitrary initial condition or an arbitrary number of layers, or both, preventing further progress in developing ES‐LMLREs. Adopting a new solution strategy, namely a conjunctive use of the variable separation method and the transfer matrix method, we develop a novel exact layered‐medium‐LRE infiltration solution, overcoming the above difficulties. First, the proposed solution is successfully validated against the Srivastava‐Yeh solution. As a feature‐demonstration example, a layered‐medium water absorption process is simulated, and our solution well captures how the heterogeneity of hydraulic parameters affects the dynamics of this process. Moreover, the proposed solution is a valuable benchmark for related numerical models.
Sleep Patterns, Pain, and Emotional Functioning in Youth With Inflammatory Bowel Disease
Authors: Szabo Margo M. , Nelson Cecelia I. , Lilly Christa L. , Manegold Stoltman Ellen M. , Riedel Brian D. , Rouster Audra S. , Duncan Christina L. 
Published: August 2023

Objective: Youth with inflammatory bowel disease (IBD) may be at increased risk for sleep difficulties due to the painful and inflammatory nature of their disease. Moreover, children and adolescents with IBD experience impairment across a variety of psychosocial domains. However, researchers have yet to investigate the complex interplay between sleep, disease-related symptoms, and psychosocial factors in this population. The purpose of this study was to examine sleep patterns, pain, and mood in pediatric IBD. Method: A sample of 25 children and adolescents with IBD ( Mage = 14.24, range = 10–18 years; 56% male) were recruited from a pediatric gastroenterology clinic. Youth wore an actigraphy watch and completed daily measures of affect and pain over the course of 14 days. Statistical analyses involved repeated measures general estimating equations. Results: No significant association for sleep with negative affect was demonstrated. Despite majority of this sample being in disease remission, results revealed that increased sleep onset latency was associated with presence of next day pain and pain was associated with better next night sleep efficiency. Conclusions: Findings of the current study suggest youth with IBD experience poor sleep quality, which is significantly related to the pain they experience. Consequently, healthcare providers should screen for and address sleep quality to optimize outcomes in their pediatric patients. Objectively assessing sleep patterns (e.g., actigraphy) may prove useful for pediatric IBD samples; however, additional research is needed to determine actigraphy’s feasibility and efficacy in assessing sleep patterns in real world settings (e.g., pediatric medical clinics). Implications for Impact Statement There is increasing awareness of the prevalence of poor sleep quality among children and adolescents with inflammatory bowel disease (IBD). This study suggests that such sleep difficulties are related to abdominal pain and may be present even for youth whose disease is in remission. It is essential to regularly screen for poor sleep quality and target these concerns in the pediatric IBD population.
Deciphering the genetic landscape of obesity: a data-driven approach to identifying plausible causal genes and therapeutic targets
Authors: Ang Mia Yang , Takeuchi Fumihiko , Kato Norihiro 
Published: August 2023

Abstract
Objectives
Genome-wide association studies (GWAS) have successfully revealed numerous susceptibility loci for obesity. However, identifying the causal genes, pathways, and tissues/cell types responsible for these associations remains a challenge, and standardized analysis workflows are lacking. Additionally, due to limited treatment options for obesity, there is a need for the development of new pharmacological therapies. This study aimed to address these issues by performing step-wise utilization of knowledgebase for gene prioritization and assessing the potential relevance of key obesity genes as therapeutic targets.

Methods and results
First, we generated a list of 28,787 obesity-associated SNPs from the publicly available GWAS dataset (approximately 800,000 individuals in the GIANT meta-analysis). Then, we prioritized 1372 genes with significant in silico evidence against genomic and transcriptomic data, including transcriptionally regulated genes in the brain from transcriptome-wide association studies. In further narrowing down the gene list, we selected key genes, which we found to be useful for the discovery of potential drug seeds as demonstrated in lipid GWAS separately. We thus identified 74 key genes for obesity, which are highly interconnected and enriched in several biological processes that contribute to obesity, including energy expenditure and homeostasis. Of 74 key genes, 37 had not been reported for the pathophysiology of obesity. Finally, by drug-gene interaction analysis, we detected 23 (of 74) key genes that are potential targets for 78 approved and marketed drugs.

Conclusions
Our results provide valuable insights into new treatment options for obesity through a data-driven approach that integrates multiple up-to-date knowledgebases.