Parallel Mean Research Articles

Design and analysis of a class of two-limb non-parasitic 2T1R parallel mechanism with decoupled motion and symbolic forward position solution - influence of optimal arrangement of limbs onto the kinematics, dynamics and stiffness

The two-limb11Throughout this paper, the two-limb parallel mechanism means that the base and moving platforms of a parallel mechanism are directly connected with two independent limbs, despite the existence of closed sub-loop in one limb (i.e., in this work, it is named as hybrid-single-ordered-chain, and HSOC for short). parallel mechanisms (PMs) can have the advantages, in terms of avoidance of mechanical collision, simple architecture, rapid configuration transformation and large workspace volume. This paper consists of two major contents. The first aspect pertains to the design of a class of two-limb PMs with two translations and one rotation (2T1R), where a family of PMs featuring two translations actuated by sliding units are proposed, with decoupled position and orientation as well as symbolic forward position solution, without parasitic motions. The second aspect is to analyze the influence of the arrangement of limbs onto the kinematic, dynamic and stiffness performance of the PMs. Using the kinematic modeling method based on topological characteristics, the unified symbolic forward and inverse position solutions of the PMs are derived, together with the workspace, rotational capacity and singularity. Finally, a comparative study regarding the kinematics, dynamics and stiffness of the two PMs is carried out to find the optimal PM configuration. This paper presents a systematic analysis for the synthesis, optimal design and performance evaluation of two-limb parallel mechanisms.

Observation-based modelling of the energetic storm particle event of 14 July 2012

Aims. We model the energetic storm particle (ESP) event of 14 July 2012 using the energetic particle acceleration and transport model named ‘PArticle Radiation Asset Directed at Interplanetary Space Exploration’ (PARADISE), together with the solar wind and coronal mass ejection (CME) model named ‘EUropean Heliospheric FORcasting Information Asset’ (EUHFORIA). The simulation results illustrate both the capabilities and limitations of the utilised models. We show that the models capture some essential structural features of the ESP event; however, for some aspects the simulations and observations diverge. We describe and, to some extent, assess the sources of errors in the modelling chain of EUHFORIA and PARADISE and discuss how they may be mitigated in the future. Methods. The PARADISE model computes energetic particle distributions in the heliosphere by solving the focused transport equation in a stochastic manner. This is done using a background solar wind configuration generated by the ideal magnetohydrodynamic module of EUHFORIA. The CME generating the ESP event is simulated by using the spheromak model of EUHFORIA, which approximates the CME’s flux rope as a linear force-free spheroidal magnetic field. In addition, a tool was developed to trace CME-driven shock waves in the EUHFORIA simulation domain. This tool is used in PARADISE to (i) inject 50 keV protons continuously at the CME-driven shock and (ii) include a foreshock and a sheath region, in which the energetic particle parallel mean free path, λ∥, decreases towards the shock wave. The value of λ∥ at the shock wave is estimated from in situ observations of the ESP event. Results. For energies below ∼1 MeV, the simulation results agree well with both the upstream and downstream components of the ESP event observed by the Advanced Composition Explorer. This suggests that these low-energy protons are mainly the result of interplanetary particle acceleration. In the downstream region, the sharp drop in the energetic particle intensities is reproduced at the entry into the following magnetic cloud, illustrating the importance of a magnetised CME model.

Superdiffusion of cosmic rays in compressible magnetized turbulence

ABSTRACT Owing to the complexity of turbulent magnetic fields, modelling the diffusion of cosmic rays is challenging. Based on the current understanding of anisotropic magnetohydrodynamic (MHD) turbulence, we use test particles to examine the cosmic rays’ superdiffusion in the direction perpendicular to the mean magnetic field. By changing Alfvén Mach number MA and sonic Mach number MS of compressible MHD simulations, our study covers a wide range of astrophysical conditions including subsonic warm gas phase and supersonic cold molecular gas. We show that freely streaming cosmic rays’ perpendicular displacement increases as 3/2 to the power of the time travelled along local magnetic field lines. This power-law index changes to 3/4 if the parallel propagation is diffusive. We find that the cosmic rays’ parallel mean free path decreases in a power-law relation of $M_\mathrm{ A}^{-2}$ in supersonic turbulence. We investigate the energy fraction of slow, fast, and Alfvénic modes and confirm the dominance of Alfvénic modes in the perpendicular superdiffusion. In particular, the energy fraction of fast mode, which is the main agent for pitch-angle scattering, increases with MA, but is insensitive to MS ≥ 2. Accordingly, our results suggest that the suppressed diffusion in supersonic molecular clouds arises primarily due to the variations of MA instead of MS.

The significance of dual-mode elastography in the diagnosis of breast lesions by physicians with different levels of experience.

This study aimed to assess the diagnostic value of dual-mode elastography for benign and malignant breast lesions and determine whether this technique can improve the diagnostic ability of physicians with different levels of experience. One hundred and eighty-three breast lesions were analyzed retrospectively, and the following values were calculated for the lesions with various shells: shear modulus (G), Young's modulus (E), shear wave velocity (Cs), and strain ratio (SR). A random forest algorithm was used to select the optimal modes for elastography. A receiver operating characteristic curve was used to assess the diagnostic efficacy for benign and malignant breast lesions. Sensitivity and specificity values were calculated to evaluate any improvements in the diagnostic efficacy of physicians with different levels of experience (junior, intermediate-level, and senior) in the evaluation of malignant breast lesions using dual-mode elastography. The best-performing mode of shear wave elastography (SWE) in the diagnosis of breast lesions was the A'min 1.0 (Cs) mode (minimum shear wave velocity of the area of interest and 1.0 mm around the area of interest), and the best-performing mode of strain elastography (SE) was the B/A' 0.5 (ratio of fat to the elasticity of the area of interest and 0.5 mm around the area of interest). When the two methods were used in series, results showed high specificity (98%), positive likelihood ratio (PLR) (21.2), and positive predictive value (PPV) (95%). Series means that if SE and SWE were malignant, the result in series was malignant, and that if either SE or SWE was benign, the result in series was benign. When the methods were used in parallel, the results showed high sensitivity (91%), negative likelihood ratio (NLR) (0.15), and negative predictive value (NPV) (89%). Parallel means that if SE and SWE were benign, the result in parallel was benign, and that if either SE or SWE was malignant, the result in parallel was malignant. When conventional ultrasound was combined with dual-mode elastography, the intermediate-level and junior physicians' diagnoses of breast lesions showed a higher sensitivity, specificity, and area under the curve than conventional ultrasound diagnosis alone. Dual-mode elastography is effective in the diagnosis of breast lesions. The sensitivity and specificity values in this study show that diagnoses made by junior and intermediate-level physicians improve when dual-mode elastography is used, although diagnoses made by senior physicians do not improve significantly.

Sectarian Identity and Mobilization Amongst the Druze: How Do Sectarian Minorities Respond to Religious Terrorism?

ABSTRACT Taking its point of departure in the sectarian dynamics in the Middle East, namely the Sunni–Shiʿa schism that is taking the largest share in the current debates, this article studies sectarian identity and religious terrorism against the Druze minority during Syria’s sect-coded civil war. It argues that while religion can act as a mobilizational tool and marker of group solidarity amongst Druze as well as amongst Sunni and Shiʿa, the Druze did not instrumentalize sectarian identity to implement their geopolitical agenda. Rather, for far too long the Druze used sectarian identity as a defense mechanism to unite against violent motifs and actions by the sectarian “other.” The latter, for our purposes, happens to be Sunni jihadist groups such as Daesh (The Islamic State or ISIS) and Jabhat al-Nusra (JAN). Further, Druze is not a tabshiri sect. Put it another way, it is a sectarian minority that prevents conversions. Therefore, for the Druze, sectarian identity had always been a marker of group solidarity only. This article brings to the fore the response of sectarian minorities to religious terrorism following the Arab Uprisings era, and stresses that sectarian mobilization has parallel means but not always similar ends.

Stochastically complete submanifolds with parallel mean curvature vector field in a Riemannian space form

Stochastically complete submanifolds with parallel mean curvature vector field in a Riemannian space form

Classification of f-biharmonic submanifolds in Lorentz space forms

Abstract In this paper, f-biharmonic submanifolds with parallel normalized mean curvature vector field in Lorentz space forms are discussed. When f f is a constant, we prove that such submanifolds have parallel mean curvature vector field with the minimal polynomial of the shape operator of degree ≤ 2 \le 2 . When f f is a function, we completely classify such pseudo-umbilical submanifolds.

A new geometric structure on tangent bundles

For a Riemannian manifold (N,g), we construct a scalar flat neutral metric G on the tangent bundle TN. The metric is locally conformally flat if and only if either N is a 2-dimensional manifold or (N,g) is a real space form. It is also shown that G is locally symmetric if and only if g is locally symmetric. We then study submanifolds in TN and, in particular, find the conditions for a curve to be geodesic. The conditions for a Lagrangian graph in the tangent bundle TN to have parallel mean curvature are studied. Finally, using the cross product in R3 we show that the space of oriented lines in R3 can be minimally isometrically embedded in TR3.

The Transport and Evolution of MHD Turbulence throughout the Heliosphere: Models and Observations

A detailed study of solar wind turbulence throughout the heliosphere in both the upwind and downwind directions is presented. We use an incompressible magnetohydrodynamic (MHD) turbulence model that includes the effects of electrons, the separation of turbulence energy into proton and electron heating, the electron heat flux, and Coulomb collisions between protons and electrons. We derive expressions for the turbulence cascade rate corresponding to the energy in forward and backward propagating modes, the fluctuating kinetic and magnetic energy, the normalized cross-helicity, and the normalized residual energy, and calculate the turbulence cascade rate from 0.17 to 75 au in the upwind and downwind directions. Finally, we use the turbulence transport models to derive cosmic ray (CR) parallel and perpendicular mean free paths (mfps) in the upwind and downwind heliocentric directions. We find that turbulence in the upwind and downwind directions is different, in part because of the asymmetric distribution of new born pickup ions in the two directions, which results in the CR mfps being different in the two directions. This is important for models that describe the modulation of cosmic rays by the solar wind.

Bonnet and Isotropically Isothermic Surfaces in 4-Dimensional Space Forms

We study the Bonnet problem for surfaces in 4-dimensional space forms, namely, to what extent a surface is determined by the metric and the mean curvature. Two isometric surfaces have the same mean curvature if there exists a parallel vector bundle isometry between their normal bundles that preserves the mean curvature vector fields. We deal with the structure of the moduli space of congruence classes of isometric surfaces with the same mean curvature and with properties inherited on a surface by this structure. The study of this problem led us to a new conformally invariant property, called isotropic isothermicity, that coincides with the usual concept of isothermicity for surfaces lying in totally umbilical hypersurfaces, and is related to lines of curvature and infinitesimal isometric deformations that preserve the mean curvature vector field. The class of isotropically isothermic surfaces includes the one of surfaces with a vertically harmonic Gauss lift and particularly the minimal surfaces, and overlaps with that of isothermic surfaces without containing the entire class. We show that if a simply connected surface is not proper Bonnet, which means that the moduli space is a finite set, then it admits either at most one, or exactly three Bonnet mates. For simply connected proper Bonnet surfaces, the moduli space is either 1-dimensional with at most two connected components diffeomorphic to the circle, or the 2-dimensional torus. We prove that simply connected Bonnet surfaces lying in totally geodesic hypersurfaces of the ambient space as surfaces of non-constant mean curvature always admit Bonnet mates that do not lie in any totally umbilical hypersurface. Such surfaces either admit exactly three Bonnet mates, or they are proper Bonnet with moduli space the torus. We show that isotropic isothermicity characterizes the proper Bonnet surfaces, and we provide relevant conditions for non-existence of Bonnet mates for compact surfaces. Moreover, we study compact surfaces that are locally proper Bonnet, and we prove that the existence of a uniform substructure on the local moduli spaces characterizes surfaces with a vertically harmonic Gauss lift that are neither minimal, nor superconformal. In particular, we show that the only compact, locally proper Bonnet surfaces with moduli space the torus, are those with nonvanishing parallel mean curvature vector field and positive genus.

Determination of linear bond Grüneisen parameter of GaAs using Extended X-ray Absorption Fine Structure (EXAFS)

The bond Grüneisen parameter of gallium arsenide’s first shell was directly evaluated using temperature-dependent Extended X-ray Absorption Fine Structure (EXAFS) data. A quasi-harmonic approach based on the anharmonic contribution to parallel Mean Square Relative Displacement (MSRD) has led to a positive and weakly temperature-dependent linear bond Grüneisen parameter (GP) of GaAs in the entire region (14–300 K). For all temperatures, we report linear bond GPs greater than those retrieved with EXAFS using an anharmonic Einstein model. The comparison with volumic Grüneisen parameters given by diffraction or dilatometric techniques shows a significant difference which could be attributed to the different definitions used to connect frequency and bond length (or lattice parameter). These results are an evidence of the inadequacy of the quasi-harmonic model to deal with local properties using EXAFS.

Numerical modeling of cosmic rays in the heliosphere: Analysis of proton data from AMS-02 and PAMELA

Galactic cosmic rays (CRs) inside the heliosphere are affected by solar modulation. To investigate this phenomenon and its underlying physical mechanisms, we have performed a data-driven analysis of the temporal dependence of the CR proton flux over the solar cycle. The modulation effect was modeled by means of stochastic simulations of cosmic particles in the heliosphere. The model were constrained using measurements of CR protons made by AMS-02 and PAMELA experiments on monthly basis from 2006 to 2017. With a global statistical analysis of these data, we have determined the key model parameters governing CR diffusion, its dependence on the particle rigidity, and its evolution over the solar cycle. Our results span over epochs of solar minimum, solar maximum, as well as epochs with magnetic reversal and opposite polarities. Along with the evolution of the CR transport parameters, we study their relationship with solar activity proxies and interplanetary parameters. We find that the rigidity dependence of the parallel mean free path of CR diffusion shows a remarkable time dependence, indicating a long-term variability in the interplanetary turbulence that interchanges across different regimes over the solar cycle. The evolution of the diffusion parameters show a delayed correlation with solar activity proxies, reflecting the dynamics of the heliospheric plasma, and distinct dependencies for opposite states of magnetic polarity, reflecting the influence of charge-sign dependent drift in the CR modulation.

Universal Discourse Representation Structure Parsing

Abstract We consider the task of crosslingual semantic parsing in the style of Discourse Representation Theory (DRT) where knowledge from annotated corpora in a resource-rich language is transferred via bitext to guide learning in other languages. We introduce Universal Discourse Representation Theory (UDRT), a variant of DRT that explicitly anchors semantic representations to tokens in the linguistic input. We develop a semantic parsing framework based on the Transformer architecture and utilize it to obtain semantic resources in multiple languages following two learning schemes. The Many-to-One approach translates non-English text to English, and then runs a relatively accurate English parser on the translated text, while the One-to-Many approach translates gold standard English to non-English text and trains multiple parsers (one per language) on the translations. Experimental results on the Parallel Meaning Bank show that our proposal outperforms strong baselines by a wide margin and can be used to construct (silver-standard) meaning banks for 99 languages.

Polarization effects in Raman spectroscopy of light‐absorbing carbon

AbstractRaman spectroscopy is widely used for characterization of carbon‐based materials including light‐absorbing carbonaceous (LAC) matter. However, information on polarization properties of these materials are generally lacking, and often the polarization characteristics of experiments are not presented in the literature thereby giving uncertainty to presented data. In this work, the polarization properties of various LACs are studied using Raman spectroscopy. The Raman spectra have been compared while varying the relative polarization, particularly the relative direction of the electric field between the incident light and the detected scattered light. Specifically, the intensity ratio between the D1 and G peaks (ID1/IG) was analyzed in parallel and perpendicular polarization configurations for samples taken from a sooting flame, in the exhaust of a soot generator and carbon blacks. In this work, the parallel and perpendicular polarization configurations mean that the polarization of the detected scattered light is parallel and orthogonal, respectively, to the linearly polarized incident light. It was found that the (ID1/IG) ratio decreased in the more ordered carbonaceous structures when changing the polarization configuration from parallel to perpendicular. Additionally, based on the depolarization ratios (Dp < 0.75), the prominent Raman peaks of LAC were found to originate from totally symmetric vibrations. For the G peak, the depolarization ratio was measured to be in the range 0.46–0.56 for all LAC materials.

Special Liouville metric with the Ricci condition

Two necessary conditions for the induced metrics of parallel mean curvature surfaces in a complex space form of complex two-dimension are observed. One is similar to the Ricci condition of the classical surface theory in Euclidean three-space and the other is related to the Liouville metric. Conversely, we prove that a special type of the Liouville metric on a domain in the Euclidean two-plane whose Gaussian curvature satisfies the differential equation similar to the Ricci condition is explicitly determined by an elliptic function. We have isometric immersions from a simply connected two-dimensional Riemannian manifold with the special type of the Liouville metric satisfying the Ricci condition to the complex hyperbolic plane with parallel mean curvature vector.

A short note on honorifics and personal articles in Spanish and Catalan and its consequences for the theory of proper names

Building on recent findings in Bernstein et al. (2019), regarding the syntactic distribution of personal articles in Catalan and honorifics in Spanish, I propose that they are pure expressives (in Potts’ (2005) sense) that take an entity as argument and return the same entity at the at-issue level and a conventionally implicated proposition in a parallel meaning dimension. If this analysis turns out to be correct, the expressive / proper name interaction in these languages will constitute a new piece of evidence against the predicative analysis of proper names. Reviewed by:José CamachoFrancesc Roca

Varying Means of Grammatical Parallelism in the Church Slavonic Translations of Psalms of the 11th–16th Centuries

As a metrically organized poetic text, the Psalter is built on the principle of substantive and formal parallelism of verses and stanzas in the Hebrew text as well as in Greek and Church Slavonic translations. In the article, based on the material of Slavic translations of different times (from the Sinai Psalter of the 11 th century to the Psalter of 1552 by Maximus the Greek), cases of assimilation / dissimilation of grammatical forms in parallel text structures are considered. The variability which arises in the process of dissimilation has neither genetic (South Slavonic vs East Slavonic, archaic vs new, standard vs non-standard forms), nor functional (literary vs non-literary forms), but rhetorical nature of stylistic variation, conditioned by the structure of the text. The analysis revealed that in early Slavonic psalter redactions the choice and the number of variable grammatical forms are limited; the texts of the 16 th century, namely the Psalms of 1552 translated by Maximus the Greek, are particularly characterized by stylistic grammatical variability, concerning the most different forms (from the substantive Gen. and Dat. cases to the aorist and perfect in the 3 rd person). The examined cases of the dissimilated grammatical forms in parallel contexts of the Psalter are supported by some original Maximus the Greek's works, so that these forms should be considered as stylistic variants of the literary Church Slavonic language.

Организация и содержание музыкально-исполнительской подготовки в высших национальных консерваториях музыки и танца Парижа и Лиона

On the wave of the multi-vectored processes in higher musical education of performing musicians in many ways conditioned by social transformations and the practice of the contemporary art of music generated by parallel means in different European countries, particularly France primarily accepted the Bologne Convention in 2008 as a convenient model, on the other hand, for broad partner interaction and mutual enrichment and, on the other hand – of an artistic “restoration” of a historically established original system of higher musical education for performers in this country. The article shows the particularities of reorganization of the structure, the principle of bestowing scholarly degrees in the two most prestigious higher educational institutions – the Paris and Lyon Higher Conservatories of Music and Dance. Conclusions are arrived at about the immense potentials and particularities of the tendencies of development of the transnational convention twovectored in its nature, the acceptance of which opens up new prospects for extending the range of acquired specializations and the intellectualization of training in higher educational institutions in our country. Keywords: system of higher education, conservatories of France, Bologne Convention.

Destroying Veronica Mars: Gentrification, Gendered Intersectionality, and the Coming of Age of Los Angeles

Destroying Veronica Mars: Gentrification, Gendered Intersectionality, and the Coming of Age of Los Angeles Susan Ingram In the summer of 2019, fans of Veronica Mars were treated to a fourth season of the critically acclaimed television series, which had played for three seasons (2004–06) before being cancelled due to low ratings despite the protests of its large, fiercely loyal fan base, who call themselves “marshmallows” as a tribute to the opening bumper of the show, which ends with Veronica noting that “people say I’m a marshmallow” (Cochran). When it became clear that Warner Bros. would not back the feature-film script that creator Rob Thomas had written as an alternate way of continuing the series, Thomas and his team turned to Kickstarter, crowdsourcing the 2014 Veronica Mars film to the tune of $5,702,153, which far surpassed the $2 million they had set out to raise, and broke several Kickstarter records in the process (Hicken; Thomas, “The Veronica Mars Movie Project”; Thomas, “Update 2”). Like the three TV seasons before it, the film garnered critical but not commercial success, grossing only $3.5 million worldwide with a budget of $6 million (Acuna), and it was only on the strength of continued fan demand that an abridged fourth season (of eight episodes vs. 64 in the first three) was made. The Veronica Mars franchise, which also includes two novels co-authored by Thomas and Jennifer Graham, Veronica Mars: The Thousand Dollar Tan Line (2014) and Veronica Mars: Mr. Kiss and Tell (2015); and a short-lived web spinoff, Play It Again, Dick, follows the eponymous young blonde hard-boiled PI as she solves crimes in Neptune, a seaside town in Southern California in the fictional spirit of Chandler’s Bay City.1 The changes that Neptune undergoes from the first season in 2004 to the fourth in 2019 are substantial, and parallel Veronica’s own coming of age as she goes from being a date-raped teenager who helps out in her father’s office after school to being a full partner in the firm, and the one who keeps it afloat when her father faces a potentially debilitating health crisis. Season Four ends with a shockingly unexpected [End Page 11] bombing, the results of which see the season end with Veronica driving out of Neptune determined never to return. Thomas admits that this plot twist was a huge gamble that could well end the series (Gennis), and it received considerable criticism (Connolly). What I am interested in in this article is how the changes that Veronica and Neptune undergo over the course of a pivotal decade and a half reflect the development of both feminism and urbanization. Comparing Veronica’s coming of age with the city’s along the parallel vectors of gentrification and generation allows me to explore what it means for Los Angeles that it has gentrified to the point that the makers of Veronica Mars no longer felt it was the right place for her. After detailing the points in the series along which Neptune and Veronica are shown to mature, I explore what these parallel transformations mean for the figure of the female private detective as well as for the city in which she lives and works. Neptune: From Noirish Suburb to Spring Break Destination At the end of the 2014 Veronica Mars film, Veronica opts to stay in Neptune, “preferring self-employed work on her home turf to a stressful, high-powered career in corporate, East Coast law” (Ingram and Reisenleitner 32). She also does so in order to be able to look after her father, Keith, who is seriously injured in the film in a car accident when someone tries to take him out for pursuing a case against the Sheriff’s Office over the planting of evidence at crime scenes involving the poorer members of Neptune’s population. When we next meet up with them in Veronica Mars: The Thousand Dollar Tan Line, we learn that [f]or the past two months he’d been able to pretend she was there to help him in his convalescence, but more and more she sensed...

AN ORIGINAL ANALYSIS ATTEMPT ON THE CONCEPT OF VALUE

İnsan bir değer varlığıdır. İnsanın bilinç sahibi oluşu, bu tanıma yol vermektedir. Bir değer varlığı olan insanın bilinç edimlerinin doğasını çözümlemeye çalışmak oldukça güçtür çünkü bilinç, nesnesi ile olan edimselliğinde tebarüz ettiği gibi nesne de bilincin edimselliğinde varlık kazanır. İnsanın bilinç varlığı olmasıyla değer varlığı olmasının koşutluğu, aynı güçlüğün değer kavramı için de geçerli olduğu anlamına gelmektedir. Değer kavramını mutlak bilinç ile özdeşleştirecek olursak, bir nesneye ilişkin değeri ise bilincin nesnesi ile olan ilişkisi ile tanımlamak veya özdeşleştirmek gerekir. Dolayısıyla varlık ve değerin aynı zeminde buluştuklarını ileri sürmekteyiz. Bu makale, bilinç varlığı olan insanın, varlık ile ilişkisinin her daim değer biçme ve değer atfetme üzerine kurulu olduğunu ileri sürmektedir.