Articulated Structures Research Articles

Comparative Morphology of the Extrinsic and Intrinsic Leg Musculature in Dictyoptera (Insecta: Blattodea, Mantodea).

Insect legs, as primarily locomotory devices, can show a tremendous variety of morphological modifications providing a multitude of usages. The prehensile raptorial forelegs of praying mantises (Mantodea) are a prominent example of true multifunctionality since they are used for walking while being efficient prey-capturing and grasping devices. Although being mostly generalist arthropod predators, various morphological adaptations due to different environmental conditions occur across Mantodea. Recently, the general mantodean morphology, and particularly their raptorial forelegs, received an increased interest. Yet, knowledge about the evolutionary transition from walking to prey-grasping legs is still scarce. From evolutionary and functional perspectives, the question arises: what changes were necessary to achieve the strongly modified raptorial forelegs-while keeping walking ability-and how does the foreleg morphology differ from the remaining four walking legs? In this context, we investigated the musculature of the raptorial forelegs in seven phylogenetically distant mantodeans, including pterothoracic legs in four of them, using high-resolution microcomputed tomography and dissection. To understand the results from an evolutionary perspective, we additionally examined all three pairs of unmodified walking legs of the closest sister group-Blattodea. We updated the knowledge of blattodean morphology, revealing differences in cuticle structures of the coxal articulation of the first pair of legs between the two orders and a shared musculature set-up in all pairs of legs among later-branching mantodeans. Interestingly, the early branching species Metallyticus splendidus and Chaeteessa sp. show several muscular characteristics, otherwise found exclusively in one or the other order, with a few procoxal muscles showing an intermediate state between the two orders. Studying the evolutionary transition from a walking leg to a raptorial leg will help to understand the character evolution of this highly specialized biomechanical system from a purely locomotory appendage to a multi-functional device with all related amenities and constraints.

Comparison of the effect of clear twin block and traditional twin block on speech: a randomized clinical trial.

To compare the effect of clear twin block (CTB) and traditional twin block (TTB) appliances on speech. In this randomized clinical trial, 18 skeletal Class II (Class II, division 1) growing patients were selected and randomly divided into CTB and TTB groups. Objective and semiobjective speech assessment tests were performed for vowel and consonant analyses at four time intervals: before (T0), immediately after (T1), 1 month after (T2), and 3 months after (T3) inserting the appliance. Data were analyzed using analysis of variance and independent t-test at the .05 significance level. Intergroup comparisons showed that the CTB group had less speech distortion immediately after insertion of the appliance (P < .05) than the TTB group; however, the differences were not significant at other time intervals. Intragroup comparisons showed that the number of distortions decreased significantly from T1 to T3 in both groups (P < .05). In contrast to CTB, the T0-T3 comparison was significant in the TTB group. Although both appliances had some effects on speech, CTB had less speech distortion immediately after insertion, which is a very crucial moment in patient compliance. Additionally, articulation structures adapted to CTB faster than to TTB.

Bi-level path tracking control of tractor semi-trailers by coordinated active front steering and differential braking

In recent years, autonomous tractor semi-trailers have been considered a promising solution for transportation on highways, ports, and large logistics centers to improve safety and efficiency. However, due to the complicated dynamics introduced by articulation structure, there are still challenges in achieving high-precision path tracking and stability control for tractor semi-trailers, especially in critical scenarios. In this work, a bi-level path tracking control scheme for the autonomous tractor semi-trailer is proposed. At the higher level, a robust model predictive controller coordinating active front steering and differential braking is devised for addressing path tracking, stability control and robustness for an autonomous tractor semi-trailer. At the lower level, incorporating a logic switching mechanism, the designed optimal braking torque distribution module and the PID-based longitudinal control module prioritize the implementation of differential braking and target speed tracking. Simulation results demonstrate that the proposed control strategy offers remarkable path tracking performance in three designed testing scenarios.

Variation of sign parameters in narrative and expository discourse

Abstract The paper presents an in-depth study of variation in sign parameters of Israeli Sign Language (ISL). We describe and analyze specific sign parameters and their sub-parameters: handshape, orientation, place of articulation, and movement, as they are distributed in two text-types: narrative and expository discourse. A group of 16 deaf native ISL signers produced 32 texts containing a total of 6,875 signs which were then analyzed from a bottom-up approach. A sub-set of 3,919 signs out of this large database (excluding signs that are inherently variable) were found eligible for the detailed distributional analysis of text-dependent variation in terms of their articulation structure, and were used for comparison between the narrative and expository productions. Our findings show that narratives attract more variation in the sign parameters compared to expository texts. The study thus highlights the impact of communicative context on the use of signs.

Unsupervised phoneme and word acquisition from continuous speech based on a hierarchical probabilistic generative model

Humans can divide the perceived continuous speech signals, which exhibit double articulation structure, into phonemes and words without explicit boundary points or labels and thus learn a language. In constructive developmental studies, learning the double articulation structure of speech signals is important for realizing robots with human-like language learning abilities. In this study, we propose a novel probabilistic generative model called the Gaussian process-hidden semi-Markov model-based double articulation analyzer (GP-HSMM-DAA), which can learn phonemes and words from continuous speech signals by hierarchically connecting two probabilistic generative models (PGMs), namely, the Gaussian process-hidden semi-Markov model and hidden semi-Markov model. In the proposed model, the parameters of each PGM are mutually and complementarily updated and learned, enabling accurate learning of the phonemes and words. The experimental results reveal that GP-HSMM-DAA can segment continuous speech into phonemes and words with higher accuracy than the conventional method.

Double Articulation Analyzer With Prosody for Unsupervised Word and Phone Discovery

Infants acquire words and phonemes from unsegmented speech signals using segmentation cues, such as distributional, prosodic, and co-occurrence cues. Many pre-existing computational models that represent the process tend to focus on distributional or prosodic cues. This paper proposes a nonparametric Bayesian probabilistic generative model called the prosodic hierarchical Dirichlet process-hidden language model (Prosodic HDP-HLM). Prosodic HDP-HLM, an extension of HDP-HLM, considers both prosodic and distributional cues within a single integrative generative model. We conducted three experiments on different types of datasets, and demonstrate the validity of the proposed method. The results show that the Prosodic DAA successfully uses prosodic cues and outperforms a method that solely uses distributional cues. The main contributions of this study are as follows: 1) We develop a probabilistic generative model for time series data including prosody that potentially has a double articulation structure; 2) We propose the Prosodic DAA by deriving the inference procedure for Prosodic HDP-HLM and show that Prosodic DAA can discover words directly from continuous human speech signals using statistical information and prosodic information in an unsupervised manner; 3) We show that prosodic cues contribute to word segmentation more in naturally distributed case words, i.e., they follow Zipf's law.

GP-HSMMに基づく二重分節化モデルによる連続音声の教師なし構造学習

Humans can divide perceived continuous speech signals into phonemes and words, which have a double articulation structure, without explicit boundary points and labels, and learn the language. Learning such a double articulation structure of speech signals is important for realizing a robot that can acquire vocabulary and have a conversation. In this paper, we propose a novel statistical model GP-HSMM-DAA (Gaussian Process Hidden Semi Markov Model-based Double Articulation Analyzer) that can learn double articulation structures of time-series data by connecting statistical models hierarchically. In the proposed model, the parameters of each statistical model are mutually updated and learned complementarily. We present that GP-HSMM-DAA can segment continuous speech into phonemes and words with higher accuracy than the baseline methods.

Piano sound phenomenon in English-language scientific discourse

Statement of the problem. The process of achieving an aesthetically appealing and artistically true piano sound has long been a subject of research for musicians. In recent decades, domestic performance practice has relied on this issue mostly on the professional literature created back in the Soviet period. But the process of integrating Ukrainian musical education and performance into the European and world cultural space requires the study of alternative sources, primarily English-language ones, that reflect the experience of performers in different countries of the world, as well as correlations and the introduction of relevant terminology into scientific and practical circulation. Analyzing recent publications, we established that the phenomenon of the piano in general and piano sound in particular is considered from different points in the works of J. Parakilas (2000), E. Hiebert (2013), V. Raad (1977), G. Fitch (2016a,b; 2022), Shen Li and R. Timmers (2021), M. Keane (2013), Chuan C. Chang (2009), I. Masters (2021), and others. The purpose of this article was to study the approaches to the phenomenon of piano sound available in the English-language scientific literature. For the first time, a number of Englishlanguage sources dedicated to the phenomenon of piano sound have been included in domestic scientific circulation. Systematic and comparative methods, as well as terminological analysis used in the study, made it possible to distinguish different contexts, in which the phenomenon of piano sound is presented in scientific discourse: performance-practical, psychological, historical, organological (due to the structural features of the instruments). Research results. One of the approaches to the study of the piano sound phenomenon is the study of the history of the piano, its place in European culture and its social functions, as in the work of J. Parakilas (2000), where the author describes the history of the functioning of the piano during the 18th–20th centuries. The sound of the piano in the historical, stylistic and organological contexts is considered by I. Masters (2021), who investigated the structural and sound features of the London and Viennese pianos (second half of the 18th century) and their influence on the specifics of the piano texture, structure of themes, articulation and stroke palette of the works of pianists and composers of the London and Vienna schools. A purely performance and practical perspective is found in Chuan C. Chang’s book (2009), which covers most aspects of piano playing. Another example of a purely practical approach to the study of piano sound is the articles by G. Fitch (2016a,b; 2022), where he considers the process of creating an aesthetically pleasing sound. Another perspective on piano sound and playing is interdisciplinary, where musicology interacts with acoustics, psychology, and physiology (Keane, 2013; Li, &amp; Timmers, 2021). Conclusions. A review of professional sources shows that the piano sound in the modern English-language scientific discourse is considered as a complex multifaceted phenomenon. The main and special concepts describing the sound of the piano are “tone”, “voicing”, “layering”. The first two terms have an ambiguous interpretation: some authors understand the quality of the instrument’s sound as the result of the performer’s actions, others as a certain manner of playing, and others as, first of all, the character of the sound determined by the design and technical condition of the instrument.

Universal Manipulation Policy Network for Articulated Objects

We introduce the Universal Manipulation Policy Network (UMPNet) -- a single image-based policy network that infers closed-loop action sequences for manipulating arbitrary articulated objects. To infer a wide range of action trajectories, the policy supports 6DoF action representation and varying trajectory length. To handle a diverse set of objects, the policy learns from objects with different articulation structures and generalizes to unseen objects or categories. The policy is trained with self-guided exploration without any human demonstrations, scripted policy, or pre-defined goal conditions. To support effective multi-step interaction, we introduce a novel Arrow-of-Time action attribute that indicates whether an action will change the object state back to the past or forward into the future. With the Arrow-of-Time inference at each interaction step, the learned policy is able to select actions that consistently lead towards or away from a given state, thereby, enabling both effective state exploration and goal-conditioned manipulation. Video is available at https://youtu.be/KqlvcL9RqKM

Kineverse: A Symbolic Articulation Model Framework for Model-Agnostic Mobile Manipulation

Service robots in the future need to execute abstract instructions such as "fetch the milk from the fridge". To translate such instructions into actionable plans, robots require in-depth background knowledge. With regards to interactions with doors and drawers, robots require articulation models that they can use for state estimation and motion planning. Existing frameworks model articulated connections as abstract concepts such as prismatic, or revolute, but do not provide a parameterized model of these connections for computation. In this paper, we introduce a novel framework that uses symbolic mathematical expressions to model articulated structures -- robots and objects alike -- in a unified and extensible manner. We provide a theoretical description of this framework, and the operations that are supported by its models, and introduce an architecture to exchange our models in robotic applications, making them as flexible as any other environmental observation. To demonstrate the utility of our approach, we employ our practical implementation Kineverse for solving common robotics tasks from state estimation and mobile manipulation, and use it further in real-world mobile robot manipulation.

A Study on the Construction of Female Subjectivity in Disney’s Animated Film Mulan in Light of Articulation Theory

Disney’s animated film Mulan is adapted from the traditional Chinese folktale “Mulan disguises herself as a man to fight on behalf of her father”. Different from the loyal and filial figure of Mulan in Chinese traditional folktale, Disney portrays Mulan as a heroine who pursues personal value and self-actualization. Although it is quite different from Mulan figure in Chinese folktale, it is found that the construction of female subjectivity in Disney’s Mulan is a double layer articulation structure after a detailed analysis of the film text from the perspective of Stuart Hall’s articulation theory. The purpose of the first layer of articulation is to construct the field of struggle for the construction of female subjectivity in the film, and the second layer aims to reveal the connotation of emancipation of Disney’s Mulan figure through an analysis of the constructive process of Mulan’s female subjectivity. Finally, it is concluded that the female subjectivity constructed in the film is based on the recognition of gender differences, integrating masculinity and femininity, and mobilizing all individuals in the society to achieve women’s emancipation and gender equality. This feminist discourse provides an alternative logic for society with women’s life experiences.

Recent Advances in 3D Human Pose Estimation: From Optimization to Implementation and Beyond

3D human pose estimation describes estimating 3D articulation structure of a person from an image or a video. The technology has massive potential because it can enable tracking people and analyzing motion in real time. Recently, much research has been conducted to optimize human pose estimation, but few works have focused on reviewing 3D human pose estimation. In this paper, we offer a comprehensive survey of the state-of-the-art methods for 3D human pose estimation, referred to as pose estimation solutions, implementations on images or videos that contain different numbers of people and advanced 3D human pose estimation techniques. Furthermore, different kinds of algorithms are further subdivided into sub-categories and compared in light of different methodologies. To the best of our knowledge, this is the first such comprehensive survey of the recent progress of 3D human pose estimation and will hopefully facilitate the completion, refinement and applications of 3D human pose estimation.

Learning skeletal articulations with neural blend shapes

Animating a newly designed character using motion capture (mocap) data is a long standing problem in computer animation. A key consideration is the skeletal structure that should correspond to the available mocap data, and the shape deformation in the joint regions, which often requires a tailored, pose-specific refinement. In this work, we develop a neural technique for articulating 3D characters using enveloping with a pre-defined skeletal structure which produces high quality pose dependent deformations. Our framework learns to rig and skin characters with the same articulation structure ( e.g. , bipeds or quadrupeds), and builds the desired skeleton hierarchy into the network architecture. Furthermore , we propose neural blend shapes - a set of corrective pose-dependent shapes which improve the deformation quality in the joint regions in order to address the notorious artifacts resulting from standard rigging and skinning. Our system estimates neural blend shapes for input meshes with arbitrary connectivity, as well as weighting coefficients which are conditioned on the input joint rotations. Unlike recent deep learning techniques which supervise the network with ground-truth rigging and skinning parameters, our approach does not assume that the training data has a specific underlying deformation model. Instead, during training, the network observes deformed shapes and learns to infer the corresponding rig, skin and blend shapes using indirect supervision. During inference, we demonstrate that our network generalizes to unseen characters with arbitrary mesh connectivity, including unrigged characters built by 3D artists. Conforming to standard skeletal animation models enables direct plug-and-play in standard animation software, as well as game engines.

Improved MLVA typing reveals a highly articulated structure in Pseudomonas syringae pv. actinidiae populations

Pseudomonas syringae pv. actinidiae (Psa) is the causal agent of the bacterial canker of kiwifruit, the most limiting disease of this cultivation worldwide. Since its first isolation and description in Japan in 1984, but especially after the pandemic started in 2008, the pathogen has been extensively studied. In the frame of intrapathovar genetic variability, five biovars have been identified and described. However, as for other bacterial pathogens, it is conceivable that a large part of the genetic diversity remains undiscovered, most likely in those areas where the pathogen and the host plant species have coevolved. Here, a Multi Locus VNTR Analysis (MLVA) assay based on 19 loci was applied to a comprehensive collection of 152 strains, representative of all the main infected areas in the world. Results were independently analysed by three different bioinformatic approaches and, besides representing a significant genetic variability between individuals, provided evidences for the presence of a conspicuous number of different populations within Psa. Some matches to the five biovars currently accepted, others seem to be somewhat related to them, but other ones emerge as completely independent. All but one of the fourteen identified populations are scattered throughout south-eastern Asia, five in China, six in Japan, and eight in Korea, with a substantial equilibrium in genetic richness among these countries; only representatives of the population corresponding to the biovar Psa3 are retrievable anywhere else in the world. The usefulness of this assay to thoroughly depict genetic variants of the pathogen is discussed.

Development of Calculation Theory for Hinged-Connected Beams on Elastic Base

The paper provides a brief review of the literature on the theory and methods of calculating hinged-connected or articulated structures on an elastic base. The author refers to the works of B. G. Korenev, G. Ya. Popov, I. A. Simvulidi, R. V. Serebryany, A. G. Yuriev, in which, using various approaches, studies have been carried out to calculate hinged-connected beams and slabs on an elastic base. From the analysis of scientific literature on the topic under consideration, it can be concluded that there is no general approach to solving this problem, which is valid for any hinged-connected beams and plates lying on any model of an elastic base under the action of an arbitrary external load. In addition, a similar problem for this type of engineering calculations is observed in the normative documents. In the Republic of Belarus, a number of industry documents have been used to calculate pavement bearing elements for various highways and track transverse structures, in which road pavements with a load-bearing element and the connection of elements between themselves (hinged or rigid) are considered in an incoherent formulation. The paper proposes a universal approach for calculating hinged-connected beams on an elastic foundation, based on the mixed method of structural mechanics, taking into account the Zhemochkin ratios for functions of the elastic medium effects. The following hypotheses and assumptions are taken into account: only normal stresses act on the contact of the beam with the base, hypotheses of the bending theory are valid for beams, hinges between the beams are cylindrical, and the distribution of contact stresses along the width of the beams is uniform. As a result of the proposed calculation, the stress-strain state of a system of hinged-connected beams on an elastic foundation has been investigated, namely: distribution of contact stresses under beams, internal forces in the beams and hinged joints, as well as settlements of the elastic foundation under them. The numerical implementation of this approach has been performed using the mathematical package Mathematica 10.4. Examples of calculation are given for different versions of hinged-connected beams and an elastic base: for three hinged-connected beams based on Winkler and seven – on an elastic half-space.

Platysma skin flap: Laryngeal repair material to produce phonatory flap vibrational wave

The platysma skin flap was used for laryngeal reconstruction after vertical partial laryngectomy to improve the postoperative voice quality of patients with T2 and T3 glottic laryngeal carcinoma. Sixty-nine patients with unilateral T2 and T3 glottic laryngeal carcinoma were included. Forty-six patients received vertical partial laryngectomy, and a platysma skin flap was used for laryngeal reconstruction. The other 23 patients underwent transoral laser microsurgery. Subjective and objective examinations were performed to evaluate laryngeal morphology after the surgery. Acceptable voice quality was achieved for 46 patients who underwent vertical partial laryngectomy. Flap vibrational waves occurred in 19 cases (41.3%). The platysma skin flap is an ideal tissue for the reconstruction of articulation structure in open surgery of T2 and T3 unilateral glottic laryngeal carcinoma.

Evolution of Language. Continuity and Discontinuity through Models and Empirical Data

Abstract. Over the last years, the debate about language evolution has been dominated by functionalist models looking for continuity among various animal species to understand language evolution and its nature. In this work, I analyze the theoretical mistakes of such approach, that ignoring structural body transformation does not allow the application of evolutionary methods to the study of functions. Here I propose a naturalistic approach, based on Evo-Devo perspective, which considers biological constraints as the necessary “mechanical trigger” upon which language function could have evolved. This framework, through the examination of the comparative study of the peripheral and central structures of vocal articulation, allows us to both avoid functional leap in language evolution and at the same time, guarantee species-specificity of language.

Integrating morphology and invivo skeletal mobility with digital models to infer function in brittle star arms.

Brittle stars (Phylum Echinodermata, Class Ophiuroidea) have evolved rapid locomotion employing muscle and skeletal elements within their (usually) five arms to apply forces in a manner analogous to that of vertebrates. Inferring the inner workings of the arm has been difficult as the skeleton is internal and many of the ossicles are sub-millimeter in size. Advances in 3D visualization and technology have made the study of movement in ophiuroids possible. We developed six virtual 3D skeletal models to demonstrate the potential range of motion of the main arm ossicles, known as vertebrae, and six virtual 3D skeletal models of non-vertebral ossicles. These models revealed the joint center and relative position of the arm ossicles during near-maximal range of motion. The models also provide a platform for the comparative evaluation of functional capabilities between disparate ophiuroid arm morphologies. We made observations on specimens of Ophioderma brevispina and Ophiothrix angulata. As these two taxa exemplify two major morphological categories of ophiuroid vertebrae, they provide a basis for an initial assessment of the functional consequences of these disparate vertebral morphologies. These models suggest potential differences in the structure of the intervertebral articulations in these two species, implying disparities in arm flexion mechanics. We also evaluated the differences in the range of motion between segments in the proximal and distal halves of the arm length in a specimen of O.brevispina, and found that the morphology of vertebrae in the distal portion of the arm allows for higher mobility than in the proximal portion. Our models of non-vertebral ossicles show that they rotate further in the direction of movement than the vertebrae themselves in order to accommodate arm flexion. These findings raise doubts over previous hypotheses regarding the functional consequences of ophiuroid arm disparity. Our study demonstrates the value of integrating experimental data and visualization of articulated structures when making functional interpretations instead of relying on observations of vertebral or segmental morphology alone. This methodological framework can be applied to other ophiuroid taxa to enable comparative functional analyses. It will also facilitate biomechanical analyses of other invertebrate groups to illuminate how appendage or locomotor function evolved.

The wing base of the palaeodictyopteran genus Dunbaria Tillyard: Where are we now?

The structure of insect wing articulation is considered as reliable source of high level characters for phylogenetic analyses. However, the correct identification of homologous structures among the main groups of Pterygota is a hotly debated issue. Therefore, the reconstruction of the wing bases in Paleozoic extinct relatives is of great interest, but at the same time it should be treated with extreme caution due to distortions caused by taphonomic effects. The present study is focused on the wing base in Dunbaria (Spilapteridae). The articulation in Dunbaria quinquefasciata is mainly formed by a prominent upright axillary plate while the humeral plate is markedly reduced. Due to unique preservation of surface relief of the axillary plate, its composition shows a detailed pattern of three fused axillary sclerites and presumable position of the sclerite 3Ax. The obtained structures were compared among Spilapteridae and to other palaeodictyopterans Ostrava nigra (Homoiopteridae) and Namuroningxia elegans (Namuroningxiidae). The comparative study uncovered two patterns of 3Ax in Dunbaria and Namuroningxia, which correspond to their different suprafamilial classification. In contrast to previous studies these new results reveal the homologous structural elements in the wing base between Paleozoic Palaeodictyoptera and their extant relatives of Ephemeroptera, Odonata and Neoptera.

Evaluation of loading dynamics and fatigue life for a forwarder half-frame articulation

Investigations were performed aimed at increasing the fatigue life of articulated load-carrying structures used in multioperational logging machines. A spatial mathematical model for estimating the loading dynamics of articulated load-carrying structures for the entire set of technological operations of the mentioned machines is developed. An approach to the simulation of a stress-strain state of an assembled structure of articulation is outlined depending on the type of technological operation performed by the machine. The results of the investigation are implemented at forest machinery enterprises in the Republic of Belarus.