Articulation Points Research Articles

Matchings in bipartite graphs with a given number of cuts

A matching in a graph is a set of pairwise nonadjacent edges. Denote by m(G,k) the number of matchings of cardinality k in a graph G. A quasi-order ⪯ is defined by G⪯H whenever m(G,k)≤m(H,k) holds for all k. Let BG1(n,γ) be the set of connected bipartite graphs with n vertices and γ cut vertices, and BG2(n,γ) be the set of connected bipartite graphs with n vertices and γ cut edges. We determine the greatest and least elements with respect to this quasi-order in BG1(n,γ) and the greatest element in BG2(n,γ) for all values of n and γ. As corollaries, we find that these graphs maximize (resp. minimize) the Hosoya index and the matching energy within the respective sets.

Toward a conceptualization of the musical self: A theoretical-methodological approach to subjectivity in independent musicians

The objective of this study is to advance a theoretical and methodological proposal for the analysis of subjectivity construction in independent musicians. Existing social and cultural theories of subjectivity have not satisfactorily addressed the artistic experience of musicians. We present an analytic model that highlights the place of language from a perspective informed by dialogical theories and which also incorporates the aesthetic dimension of subjectivity in the occupational field. By analyzing six narrative interviews, we offer a qualitative insight into how independent musicians subjectively experience their musical activity. We constructed dialogical dimensions associated with four subjective movements in the interviewees’ discourse: aesthetic, activity, authorship, and reflectivity. Our findings about the configuration of musical subjectivity yielded three core points of articulation: musical self, existential self, and musical-occupational self. The musical self emerges as a particular subjective configuration, since creative activity represents a point of vital and occupational grounding where the boundaries between work and subjective experience appear to fade. Employing the aesthetic dimension of subjectivity made it possible to add complexity to the articulation and integration of various subjective elements of a psychological and social nature that have traditionally been studied in isolation.

The Chromatic Symmetric Function of a Graph Centred at a Vertex

We discover new linear relations between the chromatic symmetric functions of certain sequences of graphs and apply these relations to find new families of $e$-positive unit interval graphs. Motivated by the results of Gebhard and Sagan, we revisit their ideas and reinterpret their equivalence relation in terms of a new quotient algebra of NCSym. We investigate the projection of the chromatic symmetric function $Y_G$ in noncommuting variables in this quotient algebra, which defines $y_{G : v}$, the chromatic symmetric function of a graph $G$ centred at a vertex $v$. We then apply our methods to $y_{G : v}$ and find new families of unit interval graphs that are $(e)$-positive, a stronger condition than classical $e$-positivity, thus confirming new cases of the $(3+1)$-free conjecture of Stanley and Stembridge. In our study of $y_{G : v}$, we also describe methods of constructing new $e$-positive graphs from given $(e)$-positive graphs and classify the $(e)$-positivity of trees and cut vertices. We moreover construct a related quotient algebra of NCQSym to prove theorems relating the coefficients of $y_{G : v}$ to acyclic orientations of graphs, including a noncommutative refinement of Stanley's sink theorem.

Analysis of the load‐bearing characteristics of hydraulic supports for top‐coal caving under the impact of coal and gangue

AbstractTo study the effect of different sizes and speeds of coal gangue falling on hydraulic supports for top‐coal caving discharge hydraulic support on the bearing characteristics of the hydraulic support, the ADAMS hydraulic support rigid‐flexible coupling analysis model was established. HyperMesh is used to flexibly process the hydraulic support, and the column and jack are equivalently replaced by spring damping system. By applying step loads of different sizes and speeds to simulate the impact force generated when the coal gangue falls on different positions of the cover beam, the dynamic response characteristics of the column, balance jack and other articulation points are obtained. Analyses show that: when the impact load is closer to the roof beam, the articulation point of the roof beam‐cover beam and the balancing jack are easy to be damaged. When the same impact load is applied to the cover beam, the faster the load is applied, the hydraulic support column and balancing jack may not be able to absorb and disperse the pressure effectively in time, resulting in the articulation points being subjected to a larger impact force, which is easy to cause damage or destruction. When different sizes and speeds of impact loads are applied to the cover beam, the latter has a greater impact on the dynamic response of the front and rear connecting rod articulation points and the cover beam‐roof beam articulation point than the former, and the hydraulic bracket will be more prone to vibration, deformation, and stress concentration, thus affecting the stability and safety of the bracket. The article is of guiding significance for designing and optimizing the structure and parameters of the hydraulic support, and improving the support performance and stability of the hydraulic support in the comprehensive release working face.

Computing the cut locus, Voronoi diagram, and signed distance function of polygons

This paper presents a new method for the computation of the generalized Voronoi diagram of planar polygons. First, we show that the vertices of the cut locus can be computed efficiently. This is achieved by enumerating the tripoints of the polygon, a superset of the cut locus vertices. This is the set of all points that are of equal distance to three distinct topological entities. Then our algorithm identifies and connects the appropriate tripoints to form the cut locus vertex connectivity graph, where edges define linear or parabolic boundary segments between the Voronoi regions, resulting in the generalized Voronoi diagram. Our proposed method is validated on complex polygon soups. We apply the algorithm to represent the exact signed distance function of the polygon by augmenting the Voronoi regions with linear and radial functions, calculating the cut locus both inside and outside.

Gangguan Perkembangan Bahasa pada Anak Usia 4 Tahun

The schipeaking in general can be interpreted as conveying one person's intentions or ideas, thoughts, concepts or contents of one's heart to another person using spoken language so that the intention can be understood by other people. Language development is the stage where children are starting to be able to convey the desired message in the form of a sequence of sounds of two or three words. Good language development, especially in speaking, enables children to express their thoughts and feelings intelligently according to the context and situation when they are speaking. This study aims to describe the condition of speech disorders experienced by 4 year old children. And investigate the factors that influence language development in early childhood. The results of the observations and analysis carried out refer to psycholinguistic studies related to language disorders. One of the symptoms in children of language and speech disorders is that there are pronunciation errors both in the mechanism of movement of the articulation points and in pronunciation. The research results show that genetic factors play a role in the speed and ability of children's language development, a social environment that is rich in interaction and language stimulation has a positive impact including the quality of conversation, vocabulary and role playing. Treatment that can be done for children who experience language and speech disorders is by doing speech therapy, oral motor, and melodic intonation. Parental education is also important in providing appropriate language stimulation. And limited language stimulation and lack of parental support can hinder children's language development. This research highlights the importance of involving active parental support to support early childhood language development.

Lhowa Phonology: A Typological Perspective

Lhowa exhibits a large inventory of forty-one consonant phonemes. In terms of points of articulation, it contains seven types of consonants, viz., labial, dental, alveolar, retroflex, palatal, velar and glottal. In terms of manner of articulation, it presents seven types of consonants, viz., stops, nasals, affricates, fricatives, trills, laterals and approximants. In terms of voicing, there are two types of consonant phonemes, viz., voiceless and voiced. Lhowa has voiceless unaspirated, voiceless aspirated, voiced murmured and voiceless murmured sounds. It exhibits a distinct consonant distribution. Lhowa has eight basic and two fronted vowels. There are four diphthongs. Lhowa displays a moderately complex syllable structure. It presents a canonical structure of the syllable in which V is obligatory and other constituents, (Ci, initial consonant), (X, voiced palatal approximant), and (Cf, final consonant) are optional. Lhowa permits only five types of syllable patterns. Each syllable is intrinsically high or low. It exhibits simple tone system. The high vs. low tone is distinguished only on the first syllable of a word. In Lhowa, like in Lhasa Tibetan, compound words demonstrate four types of tone melodies, viz., HH, LH, LL and HL.

A characterization for fuzzy strong cut vertices and fuzzy strong cut edges

Cut vertices and cut edges are valuable for analyzing connectivity problems in classical graph theory. However, they cannot deal with certain fuzzy problems. In order to solve this problem, this paper introduces the definitions of fuzzy strong cut vertices and fuzzy strong cut edges, and characterizes fuzzy strong cut vertices and fuzzy strong cut edges in fuzzy trees, complete fuzzy graphs, and fuzzy cycles. Finally, practical applications verify the effectiveness of the theory in network stability analysis.

Study on the Nodal Composite Bearing Performance of Nontruncated PHC Pipe Pile and Bearing Platform.

In this paper, low circumferential reciprocating load foot-scale tests were performed on two nontruncated PHC B 600 130 tubular piles with bearing nodes to characterize the damage process and morphology of the specimens and to investigate the load-carrying performance of the members. The test results reveal that under the action of tensile-bending-shear loading, the bearing concrete in the node area buckles and is damaged, the anchored reinforcement in the node area yields, the constraint is weakened, an articulation point is formed, and the node rotational capacity increases. When the embedment depth increases from 200 mm to 300 mm, the ultimate bearing capacities of the positive and negative nodes increase by 31.04% and 36.16%, respectively. A numerical simulation is used to verify the test results. Considering the four types of piles without truncated nodes, the numerical simulation is used to analyze the node-bearing capacity at different embedment depths. Finally, a preferred node type is proposed as follows: a terminal plate welded anchor bar and pipe pile core-filled longitudinal reinforcement anchored into the bearing node, with a preferred embedment depth of 250 mm.

Accompaniment Application of the Talaqqi Method for Increase Ability Reading the Qur’an, Ladies of the Assembly Ta'lim Pandai Sikek

The "Majelis Ta'lim Pandai Sikek" is a group of community mothers who are active in Quran reading activities in mosques. Many issues arise in Quran reading, such as a lack of understanding of Quranic reading, where individuals merely read without grasping the Makharij al Huruf (articulation points of letters) or understanding the meanings of Quranic verses. To address this, specific methods are needed to enhance the Quran reading abilities of the mothers in the Majelis Ta'lim Pandai Sikek community. The Talaqqi method has been proven effective in improving Quranic recitation skills. The goal of this activity is to provide guidance to the Pandai Sikek community in improving their Quranic recitation using the Talaqqi method. This activity is conducted by lecturers from the University of Muhammadiyah West Sumatra and students from the Community Service Program (KKNT) of the As-Sunnah Islamic High School in Deli Serdang. The results indicate an improvement in the Quranic recitation abilities of the Pandai Sikek community. Initially, twenty mothers faced issues with Quranic recitation related to articulation points, but by the end of the program, seventeen mothers could recite fluently according to the correct articulation points. Four mothers who initially struggled with Quranic recitation could read fluently by the end of the program. Challenges encountered during the implementation of the activity include some mothers leaving the sessions midway to attend to household activities.

Análisis de los Rasgos Distintivos en la Lengua de Señas Peruana (LSP)

This research focuses on the following objectives: 1) to document and describe the distinctive function that has phonological value, and 2) to identify the distinctive features in Peruvian Sign Language (PSL) in the area of manual configuration (point of articulation, movement, space) and non-manual features. In this sense, it contributes to the study of one aspect of the phonology of PSL. For this purpose, filming was carried out and language users were consulted. The methodology included fieldwork with a group of deaf people in Lima. This exploration is pioneering for LSP, since it constitutes a first effort to provide empirical evidence on the distinctive functions of manual forms in this system. To this end, it is shown that sign language has a phonology whose basic elements (distinctive features) can be identified using the same methods as in spoken languages.

Graphs with Many Independent Vertex Cuts

Graphs with Many Independent Vertex Cuts

On blockers and transversals of maximum independent sets in co-comparability graphs

In this paper, we consider the following two problems: (i) Deletion Blocker (α) where we are given an undirected graph G=(V,E) and two integers k,d≥1 and ask whether there exists a subset of vertices S⊆V with |S|≤k such that α(G−S)≤α(G)−d, that is the independence number of G decreases by at least d after having removed the vertices from S; (ii) Transversal (α) where we are given an undirected graph G=(V,E) and two integers k,d≥1 and ask whether there exists a subset of vertices S⊆V with |S|≤k such that for every maximum independent set I we have |I∩S|≥d. We show that both problems are polynomial-time solvable in the class of co-comparability graphs by reducing them to the well-known Vertex Cut problem. Our results generalise a result of Chang et al. (2001) and a recent result of Hoang et al. (2023).

Dual mobility in primary total hip arthroplasty: A temptation from the devil or a blessing from above.

Dual mobility (DM) bearings have gained significant attention in the field of total hip arthroplasty (THA) as a valid treatment option in cases of revision for instability after THA whereas its use in primary THA is still a matter of debate. This manuscript explores the pathology, incidence, diagnosis, treatment options, prognosis, ongoing studies in the literature, and future perspectives related to the use of DM bearings employed in primary THA. DM bearings are primarily designed to address one of the major concerns in THA: Instability of the prosthetic hip. Instability is both for the surgeon and the patient a devastating postoperative complication, leading to significant pain and subsequent apprehension by the patient and may require revision surgeries. The use of DM implants poses the worry of wear-related complications, such as accelerated polyethylene wear and osteolysis, which also pose challenges to long-term implant survival. This technique has seen a steady rise in recent years, with multiple studies reporting favorable outcomes. The incidence of their utilization varies among institutions and surgeons, reflecting differing preferences and patient populations. The diagnosis of instability and wear-related complications in THA often involves clinical assessment, imaging modalities such as X-rays, computed tomography scans, and sometimes advanced imaging techniques like magnetic resonance imaging. DM bearings can be considered as an option when patients present neurologic pathologies such as Parkinson's disease or recurrent dislocations after THA. DM bearings provide an additional articulation point within the implant, facilitating a greater range of motion and inherent stability. This design allows for reduced risk of dislocation and improved functional outcomes. Various implant manufacturers offer different designs and sizes of DM bearings to suit individual patient needs. Current literature suggests that the use of DM bearings in primary THA has demonstrated promising outcomes in terms of enhanced stability, reduced dislocation rates, and improved patient satisfaction. However, long-term studies with larger patient cohorts are necessary to establish the durability and longevity of these implants. Several ongoing studies are investigating the role of DM bearings in primary THA. These studies focus on evaluating long-term implant survivorship, assessing wear patterns, analyzing patient-reported outcomes, and comparing the effectiveness of DM bearings with traditional THA designs. The future of DM bearings in primary THA holds potential for further advancements. Research efforts are aimed at refining implant materials, optimizing designs, and studying the influence of surgical techniques on implant performance. Additionally, continued investigation into the long-term outcomes and cost-effectiveness of DM bearings will play a crucial role in shaping their future use. While further research is warranted, the current evidence supports their potential as a beneficial solution in improving surgical outcomes and patient satisfaction.

Cohen–Macaulay binomial edge ideals in terms of blocks with whiskers

For a graph [Formula: see text] and the binomial edge ideal [Formula: see text] of [Formula: see text], Bolognini et al. have proved the following: [Formula: see text] is strongly unmixed [Formula: see text][Formula: see text] is Cohen–Macaulay [Formula: see text][Formula: see text] is accessible. Moreover, they have conjectured that the converse of these implications is true. Accessible and strongly unmixed properties are purely combinatorial. We give some motivations to focus only on blocks with whiskers for the characterization of all [Formula: see text] with Cohen–Macaulay [Formula: see text]. We show that accessible and strongly unmixed properties of [Formula: see text] depend only on the corresponding properties of its blocks with whiskers and vice versa. We give a new family of graphs whose binomial edge ideals are Cohen–Macaulay, and from that family, we classify all [Formula: see text]-regular [Formula: see text]-connected graphs, with the property that, after attaching some special whiskers to it, the binomial edge ideals become Cohen–Macaulay. To prove the Cohen–Macaulay conjecture, it is enough to show that every non-complete accessible graph [Formula: see text] has a cut vertex [Formula: see text] such that [Formula: see text] is accessible. We show that any non-complete accessible graph [Formula: see text] having at most three cut vertices has a cut vertex [Formula: see text] for which [Formula: see text] is accessible.

Getting linear time in graphs of bounded neighborhood diversity

AbstractParameterized complexity, introduced to efficiently solve NP‐hard problems for small values of a fixed parameter, has been recently used as a tool to speed up algorithms for tractable problems. Following this line of research, we design algorithms parameterized by neighborhood diversity () for several graph theoretic problems in : Maximum ‐Matching, Triangle Counting and Listing, Girth, Global Minimum Vertex Cut, and Perfect Graphs Recognition. Such problems are known to admit algorithms parameterized by modular‐width () and consequently—as is a special case of —by . However, the proposed novel algorithms allow for improving the computational complexity from time —where and denote, respectively, the number of vertices and edges in the input graph—to time which is only additive in the size of the input. Then we consider some classical NP‐hard problems (Maximum independent set, Maximum clique, and Minimum dominating set) and show that for several classes of hereditary graphs, they admit linear time algorithms for sufficiently small—nonnecessarily constant—values of the neighborhood diversity parameter.

Production of a guide in Brazilian Sign Language for chemical laboratory utensils

The inclusion of deaf people in the Brazilian educational system is guaranteed by the use of Brazilian Sign Language (Libras). It is important that the learning process of these students, especially when dealing with abstract concepts such as those related to Chemistry, is offered based on teaching tools that cover this language. The objective of this work was to develop a guide with signs in Libras, already existing in the literature, of chemistry laboratory materials as a didactic device aiming to promote inclusion and facilitate access to experimental chemistry teaching for deaf students. The work began with meetings to plan the preparation of the booklet and choose the most common materials in laboratory classes (analytical balance, volumetric flask, beaker, burette, Erlenmeyer flask, funnel, suction bulb, volumetric and graduated pipettes, beaker and glass clock) accompanied by searching for the corresponding sign in Libras. The guide was created considering the five Libras parameters: point of articulation, movement, facial/body expression, configuration and orientation of the hands. Therefore, the material created constitutes a facilitator and important tool for interaction between teacher and student in laboratory classes, resulting in a more dynamic and efficient teaching and learning process for the target audience.

A Pseudo-Deterministic Noisy Extremal Optimization algorithm for the pairwise connectivity Critical Node Detection Problem

Abstract The critical node detection problem is a central task in computational graph theory due to its large applicability, consisting in deleting $k$ nodes to minimize a certain graph measure. In this article, we propose a new Extremal Optimization-based approach, the Pseudo-Deterministic Noisy Extremal Optimization (PDNEO) algorithm, to solve the Critical Node Detection variant in which the pairwise connectivity is minimized. PDNEO uses an adaptive pseudo-deterministic parameter to switch between random nodes and articulation points during the search, as well as other features, such as noise induction to preserve diversity, greedy search to better exploit the search space and a greater search space exploration mechanism. Numerical experiments on synthetic and real-world networks show the effectiveness of the proposed algorithm compared with existing methods.

Bearing Performance of Prestressed High-Strength Concrete Pipe Pile Cap Connections under Truncated Pile Conditions

To investigate the load-carrying performance of the nodes between tubular piles and bearing platforms, low circumferential reciprocating load foot-scale tests were performed on two truncated PHC B 600 130 tubular piles. The development law of node destruction was explored. The test results revealed that under the action of tensile–bending–shear loading, the bearing concrete in the node area buckled and was damaged, and an articulation point was formed. When the embedment depth increased from 200 mm to 300 mm, the ultimate bearing capacities of the positive and negative nodes increased by 57.60% and 54.60%, respectively. Numerical simulation was used to analyze the bearing capacities of nodes with different types and embedment depths. Formulas for the bearing capacity of the nodes were proposed. Furthermore, two preferred node types were proposed as follows: pipe pile core-filled longitudinal reinforcement anchored to the bearing node and pipe pile body longitudinal reinforcement anchored to the bearing node + pipe pile core-filled longitudinal reinforcement anchored to the bearing node, with preferred embedment depths of 350 mm and 200 mm, respectively.

Eigenvalue multiplicity of a graph in terms of the number of external vertices

The multiplicity of an eigenvalue λ of a graph G is denoted by m(G,λ). In a connected graph G with at least two vertices, a vertex is called external if it is not a cut vertex. In a tree, an external vertex is exactly a pendant vertex. Let ϵ(G) be the number of external vertices in G. In this paper, we prove that m(G,λ)≤ϵ(G)−1 for any λ and characterize the extremal graphs with m(G,−1)=ϵ(G)−1, which generalizes the main result of Wang et al. [Linear Multi. Alg., 2020] from a tree to an arbitrary connected graph.