Articulation Points Research Articles

P3-convexity on graphs with diameter two: Computing hull and interval numbers

Given a finite, simple, and undirected graph G = ( V , E ) , a P 3 -convex set of G is a set S ⊆ V ( G ) such that every vertex of V ( G ) ∖ S has at most one neighbor in S , and the P 3 -convex hull of a vertex subset S ′ of G is the smallest P 3 -convex set containing S ′ . The P 3 -hull number h ( G ) is the cardinality of the smallest set of vertices whose P 3 -convex hull is V ( G ) . In this paper, we establish some bounds on the P 3 -hull number of graphs with diameter two. Particularly, for a biconnected diameter-two graph G it holds that h ( G ) ≤ ⌈ log ( Δ ( G ) + 1 ) ⌉ + 1 , while a non-biconnected diameter-two graph G has h ( G ) = c c ( G − v ) , where v is a cut vertex of G and c c ( G − v ) is the number of connected components of G [ V ∖ { v } ] . In addition, we show that the P 3 -hull number of biconnected C 6 -free diameter-two graphs is at most 4, while for strongly regular graphs G = G ( n , k , b , c ) it holds that h ( G ) ≤ min { ⌈ k 1 + b ⌉ + 1 , ⌈ log c + 1 ( k . c + 1 ) ⌉ + 1 } . Finally, we consider the P 3 -interval number, which is the cardinality of the smallest set S of vertices such that every vertex not in S has two neighbors in this set. We show that computing the P 3 -interval number on diameter-two split graphs is NP - complete .

Hamiltonian in 5-Connected Graph

One of the branches of mathematics that studies the properties of graphs is graph theory. The purpose of this study is to find out how to prove the Hamiltonian on a 5-connected graph. Through the stages, including modeling a complete graph, as well as modeling a 5-connected graph using vertices and cut edges, it was found that is a graph that satisfies the characteristics of a 5-connected graph. Analysis of Hamiltonian on 5-connected graph that 5-connected graph is Hamilton's invention, but it is not uniquely Hamiltonian because it has more than one Hamiltonian circuit.Keywords: k-connected graph, Hamiltonian, vertex cuts

Differentiation of skull morphology and cranial kinesis in common toads

We examined the cranial morphology and cranial kinesis of the common toads Bufo bufo and B. spinosus with micro-computed tomography and geometric morphometrics and compared the results with published data for related species in a phylogenetic context. The species significantly diverge in skull shape. The skull of B. spinosus is shorter and higher, with a ventral arm of the squamosal bone and the jaw articulation point positioned perpendicular to the braincase, in comparison with a more lateral position in B. bufo. In either species, females have a shorter snout and a higher and wider skull at the jaw articulation point that is positioned more posteriorly, in comparison with conspecific males. High variation in the amount of bone ossification was recorded in both species, ranging from scarcely ossified and loosely connected bones to highly ossified and firmly connected bones. We also found that skull shape and inferred kinetic properties of the skull are highly variable across the Bufonini tribe. However, sample sizes are mostly small and intraspecific variation is high, which might compromise the analyses. Overall, the results suggest that developmental plasticity produces high variation in ossification and cranial kinesis, affecting individuals’ feeding performances. At the population level, this variation supports an efficient exploitation of the habitat and may promote morphological adaptation in a changing environment.

Bilingual dictionary generation and enrichment via graph exploration

In recent years, we have witnessed a steady growth of linguistic information represented and exposed as linked data on the Web. Such linguistic linked data have stimulated the development and use of openly available linguistic knowledge graphs, as is the case with the Apertium RDF, a collection of interconnected bilingual dictionaries represented and accessible through Semantic Web standards. In this work, we explore techniques that exploit the graph nature of bilingual dictionaries to automatically infer new links (translations). We build upon a cycle density based method: partitioning the graph into biconnected components for a speed-up, and simplifying the pipeline through a careful structural analysis that reduces hyperparameter tuning requirements. We also analyse the shortcomings of traditional evaluation metrics used for translation inference and propose to complement them with new ones, both-word precision (BWP) and both-word recall (BWR), aimed at being more informative of algorithmic improvements. Over twenty-seven language pairs, our algorithm produces dictionaries about 70% the size of existing Apertium RDF dictionaries at a high BWP of 85% from scratch within a minute. Human evaluation shows that 78% of the additional translations generated for dictionary enrichment are correct as well. We further describe an interesting use-case: inferring synonyms within a single language, on which our initial human-based evaluation shows an average accuracy of 84%. We release our tool as free/open-source software which can not only be applied to RDF data and Apertium dictionaries, but is also easily usable for other formats and communities.

On -gain graphs with few positive eigenvalues

Let T4={1,−1,i,−i} be the group of fourth roots of unit. A T4-gain graph is a graph where each orientation of an edge is given a complex unit in T4, which is the inverse of the complex unit assigned to the opposite orientation. In this paper, we characterize the structure of the T4-gain graphs with exactly one positive eigenvalue and determine the T4-gain graphs with cut vertices having exactly two positive eigenvalues. Our results extend some parallel ones about mixed graphs and signed graphs.

Study on a Strong and Weak n-Connected Total Perfect k-Dominating set in Fuzzy Graphs

In this paper, the concept of a strong n-Connected Total Perfect k-connected total perfect k-dominating set and a weak n-connected total perfect k-dominating set in fuzzy graphs is introduced. In the current work, the triple-connected total perfect dominating set is modified to an n-connected total perfect k-dominating set nctpkD(G) and number γnctpD(G). New definitions are compared with old ones. Strong and weak n-connected total perfect k-dominating set and number of fuzzy graphs are obtained. The results of those fuzzy sets are discussed with the definitions of spanning fuzzy graphs, strong and weak arcs, dominating sets, perfect dominating sets, generalization of triple-connected total perfect dominating sets of fuzzy graphs, complete, connected, bipartite, cut node, tree, bridge and some other new notions of fuzzy graphs which are analyzed with a strong and weak nctpkD(G) set of fuzzy graphs. The order and size of the strong and weak nctpkD(G) fuzzy set are studied. Additionally, a few related theorems and statements are analyzed.

Dynastic Potential Crossover Operator.

An optimal recombination operator for two-parent solutions provides the best solution among those that take the value for each variable from one of the parents (gene transmission property). If the solutions are bit strings, the offspring of an optimal recombination operator is optimal in the smallest hyperplane containing the two parent solutions. Exploring this hyperplane is computationally costly, in general, requiring exponential time in the worst case. However, when the variable interaction graph of the objective function is sparse, exploration can be done in polynomial time. In this article, we present a recombination operator, called Dynastic Potential Crossover (DPX), that runs in polynomial time and behaves like an optimal recombination operator for low-epistasis combinatorial problems. We compare this operator, both theoretically and experimentally, with traditional crossover operators, like uniform crossover and network crossover, and with two recently defined efficient recombination operators: partition crossover and articulation points partition crossover. The empirical comparison uses NKQ Landscapes and MAX-SAT instances. DPX outperforms the other crossover operators in terms of quality of the offspring and provides better results included in a trajectory and a population-based metaheuristic, but it requires more time and memory to compute the offspring.

Hunminjeongeum Phonetics (I): Phonetic and Phoniatric Consideration for Explanation of Designs of Middle Vowel Letters

Hunminjeongeum was made by the Great King Sejong, and composed of 17 consonant and 11 vowel letters. All the 28 letters were made according to the shape of vocal organ or space at the point of articulation for each letters. This review article focused on phonetic and phoniatric consideration for explanation of the designs of the middle vowel letters, especially three main vowel letters [ • (天, heaven), ㅡ (地, earth), ㅣ (人, human)] using video-fluoroscopic evaluation as well as computed tomography scanning, etc. During articulating / • / sound, a ball-like space at frontal portion of the oral cavity was found, tongue was contracted, and sound was deep (舌 縮而聲深). During /ㅡ/ sound, a flat air space between oral tongue and hard palate was created. Tongue was slightly contacted neither deep nor shallow (舌小縮而聲不深不淺). During /ㅣ/ sound, tongue was not contacted and Sound is light (舌不縮而聲淺). Tongue was moved forward making longitudinal oro-pharyngeal air space. So, I’d like to suggest that we had better change the explanation drawing from a philosophical modeling to a more scientific modeling from real vocal tract space modeling during articulating middle vowels of Hunminjeongeum.

Treewidth-based algorithms for the small parsimony problem on networks

BackgroundPhylogenetic reconstruction is one of the paramount challenges of contemporary bioinformatics. A subtask of existing tree reconstruction algorithms is modeled by the Small Parsimony problem: given a tree T and an assignment of character-states to its leaves, assign states to the internal nodes of T such as to minimize the parsimony score, that is, the number of edges of T connecting nodes with different states. While this problem is polynomial-time solvable on trees, the matter is more complicated if T contains reticulate events such as hybridizations or recombinations, i.e. when T is a network. Indeed, three different versions of the parsimony score on networks have been proposed and each of them is NP-hard to decide. Existing parameterized algorithms focus on combining the number c of possible character-states with the number of reticulate events (per biconnected component).ResultsWe consider the parameter treewidth t of the underlying undirected graph of the input network, presenting dynamic programming algorithms for (slight generalizations of) all three versions of the parsimony problem on size-n networks running in times c^t {n^{O(1)}}, (3c)^t {n^{O(1)}}, and 6^{tc}n^{O(1)}, respectively. Our algorithms use a formulation of the treewidth that may facilitate formalizing treewidth-based dynamic programming algorithms on phylogenetic networks for other problems.ConclusionsOur algorithms allow the computation of the three popular parsimony scores, modeling the evolutionary development of a (multistate) character on a given phylogenetic network of low treewidth. Our results subsume and improve previously known algorithm for all three variants. While our results rely on being given a “good” tree-decomposition of the input, encouraging theoretical results as well as practical implementations producing them are publicly available. We present a reformulation of tree decompositions in terms of “agreeing trees” on the same set of nodes. As this formulation may come more natural to researchers and engineers developing algorithms for phylogenetic networks, we hope to render exploiting the input network’s treewidth as parameter more accessible to this audience.

Kinematic and dynamic investigation of a novel inertial propulsion drive

Today there is a great deal of controversy over the operation of inertial propulsion drives (IPD), as they challenge the laws of Newtonian mechanics. Starting with the last decades of the previous century, many devices that use the centrifugal force to generate linear propulsion were patented. Regrettably, whether we are talking about the initial, or the most recent attempts, only a few of these systems passed the patent stage and were involved for practical applications.The aim of this paper is to present an IPD, developed by the authors, which uses for generating linear motion the kinetic energy of several masses, placed in the articulation points of the links of a chain drive. The masses placed equidistantly along the half-length of the chain perform a complex movement, consisting of the specific displacement of the chain elements and a rotation around an axis, that is parallel to the line which joins the centres of the chain wheels. After deducting the equations of the geometric coordinates of the masses, the total propulsion force was computed. The obtained results are supporting the ability of the IPD to generate propulsive force and linear motion.

Burying the Dead at Ayawiri: Mortuary Diversity and Postmortem Manipulation at an Andean Hillfort (AD 1100–1450)

This article presents results from the excavation and analysis of 11 slab-cist tombs associated with the site of Ayawiri, one of the largest hillforts in the western Lake Titicaca Basin during the Late Intermediate period (LIP; AD 1100–1450). These semi-subterranean tombs typically contain commingled human remains. Variation between and within tombs in the number of individuals, the body parts represented, and the degree of skeletal articulation points to a complex burial practice that likely involved tomb reopening, successive burial, and even the deposition of select body parts. Demographic and mortuary profiles suggest that burial practices were decentralized and flexible, structured by shared attitudes toward “the dead” and the dead body but also subject to the prerogatives and preferences of semi-autonomous corporate groups. This study advances our understanding of a lesser-known mortuary tradition in the Lake Titicaca Basin—one long overshadowed by more prominent burial towers (chullpas)—and sheds new light on the complex interactions that took place between the living and the dead during the LIP.

Revolution and reality shows: Nepal’s CPN and the media worlds of late capitalism

As performance reality television shows have become popular in Nepal, singers, musicians and dancers from the various communist parties’ cultural groups have begun to take part in them and draw on them for artistic inspiration. Yet reality shows are also closely associated with neo-liberal capitalism, and these artists’ participation has thus been criticized by some on the political left. This article examines the resulting interaction of aesthetics and values when communist artists, reality show expectations and cultural criticism meet. I draw on twenty years’ engagement with Nepal’s music industry as a performer and ethnographer, and in-person and online fieldwork with communist cultural groups between 2012 and 2021. I focus on artists associated with the far-left party known officially as the Communist Party of Nepal and informally as Biplav’s CPN; a party that emerged from the former CPN (Maoist). Outlining points of articulation and conflict between the values of these Maoist artists and of commercial music and dance competition reality shows, I argue that as communists living in late capitalism, these artists strive to use reality shows as platforms and as sources of artistic inspiration to shape reality and inspire others towards their dreams of creating a more egalitarian society.

Distributed cohesive configuration controller for a swarm with low‐cost platforms

AbstractThis study presents a cohesive configuration controller for distributed space coverage by a swarm of robots. The goal is to build a dense, convex network that is robust against disconnection while robots are flocking with only incomplete knowledge about the network. The controller is an integrated framework of two different algorithms. First, we present a boundary force algorithm: physics‐based swarm intelligence that borrows the concept of surface tension force between liquid molecules. The combination of such a force with conventional flocking produces a convex and dense configuration without knowledge of the complete geometry of a robot network. Second, robots distributively determine when a configuration is on the verge of disconnection by identifying a local articulation point—a region where the removal of a single robot will change the local topology. When such a point is detected, robots switch their behavior to clustering, which aggregates them around the vulnerable region to remove every articulation point and retain a connected configuration. Finally, we introduced an index that objectively represents the level of risk of a robot configuration against the massive fragmentation, called vulnerability index. We provide theoretical performance analyses of each algorithm and validate the results with simulations and experiments using a set of low‐cost robots.

Quantum walks do not like bridges

We consider graphs with two cut vertices joined by a path with one or two edges, and prove that there can be no quantum perfect state transfer between these vertices, unless the graph has no other vertex. We achieve this result by applying the 1-sum lemma for the characteristic polynomial of graphs, the neutrino identities that relate entries of eigenprojectors and eigenvalues, and variational principles for eigenvalues (Cauchy interlacing theorem, Weyl inequalities and Wielandt minimax principle). We see our result as an intermediate step to broaden the understanding of how connectivity plays a key role in quantum walks, and as further evidence of the conjecture that no tree on four or more vertices admits state transfer. We conclude with some open problems.

À propos de l’expérience de la torture

The large influx of asylum seekers confronts public mental health services with the suffering resulting from extreme political violence. Among these patients, survivors of torture present a unique clinical profile of which clinicians should be made aware. While certain researchers have proposed useful concepts, the statements of witnesses and the writings of clinicians constitute the point of articulation between theory and practice. In this article, we will attempt to understand the ways in which torture results in psychosis (“a laboratory of psychosis”), notably through the specific and ambiguous role of the imaginary. A specific focus will be dedicated to the processes of humiliation, which illuminate a dialectic between the body and the mind, between the physical wounds and the long-lasting injuries inflicted on the soul; torture causing, intentionally, the possibility of a rupture between the ego and the ideal of the self. Finally, the article will critically examine the role of the therapist; so that clinicians will be able find a favorable resolution to the pathogenic conflicts involved.

Efficient Two-Dimensional Defect-Free Dual-Species Atom Arrays Rearrangement Algorithm with Near-Fewest Atom Moves

Dual-species single-atom array in optical tweezers has several advantages over the single-species atom array as a platform for quantum computing and quantum simulation. Thus, creating the defect-free dual-species single-atom array with atom numbers over hundreds is essential. As recent experiments demonstrated, one of the main difficulties lies in designing an efficient algorithm to rearrange the stochastically loaded dual-species atoms arrays into arbitrary demanded configurations. We propose a heuristic connectivity optimization algorithm to provide the near-fewest number of atom moves. Our algorithm introduces the concept of using articulation points in an undirected graph to optimize connectivity as a critical consideration for arranging the atom moving paths. Tested in array size of hundreds atoms and various configurations, our algorithm shows a high success rate (>97%), low extra atom moves ratio, good scalability, and flexibility. Furthermore, we propose a complementary step to solve the problem of atom loss during the rearrangement.

Super Connected Direct Product of Graphs and Cycles

The topology of an interconnection network can be modeled by a graph G=(V(G),E(G)). The connectivity of graph G is a parameter used to measure the reliability of a corresponding network. The direct product is an important graph product. This paper mainly focuses on the super connectedness of the direct product of graphs and cycles. The connectivity of G, denoted by κ(G), is the size of a minimum vertex set S⊆V(G) such that G−S is not connected or has only one vertex. The graph G is said to be super connected, simply super-κ, if every minimum vertex cut is the neighborhood of a vertex with minimum degree. The direct product of two graphs G and H, denoted by G×H, is the graph with vertex set V(G×H)=V(G)×V(H) and edge set E(G×H)={(u1,v1)(u2,v2)|u1u2∈E(G),v1v2∈E(H)}. In this paper, we give some sufficient conditions for the direct product G×Cn to be super connected, where Cn is the cycle on n vertices. Furthermore, those sufficient conditions are the best possible.

Groin and anterolateral thigh flaps for hemiglossectomy reconstruction: A comparison based on Japanese speech intelligibility

ObjectiveThe differences in speech function between groin flap reconstruction and anterolateral thigh (ALT) flap reconstruction after hemiglossectomy have not been clarified to date. This study aimed to compare Japanese speech intelligibility after hemiglossectomy reconstruction using groin and ALT flaps of similar thickness. MethodsData of patients who underwent hemiglossectomy reconstruction with groin or ALT flaps between April 2010 and March 2020 were collected from the medical chart database. The ALT flap was the first choice for hemiglossectomy reconstruction, and a groin flap was used when the ALT flap was >10 mm. Cases in which speech intelligibility assessments based on Hirose's 10-point scoring system, the TKR speech test, and the Japanese speech intelligibility test for 100 monosyllables were performed after 6 months postoperatively were extracted. The per-patient scores for each assessment were initially compared between the two flap groups. Then, the results of the Japanese speech intelligibility test for 100 monosyllables were reanalyzed on a syllable-by-syllable basis. ResultsAmong the 44 hemiglossectomy patients who underwent free-flap reconstruction during the study period, 14 (seven each in the groin flap and ALT flap groups) underwent all three conventional speech intelligibility assessments after 6 months postoperatively. The two groups showed no significant difference in postoperative speech intelligibility in any of the three patient assessment methods. However, in intergroup comparisons based on per-syllable accuracy for each of the 100 monosyllables, the groin flap group showed 19 syllables with a significantly higher accuracy, whereas the ALT flap group showed one such syllable. In particular, five out of the six alveolar consonants (/t/ and /d/) were more accurately articulated in the groin flap group. Per-syllable accuracy was significantly higher in the groin flap group (74.6% vs. 66.7%; 95% confidence interval: 4.6–11.1, p < 0.001). ConclusionIn patients undergoing hemiglossectomy reconstruction, our new analysis method, which compared intelligibility by syllables, showed that the groin flap yielded higher speech intelligibility than the ALT flap. This difference was evident at all four articulation points involving the tongue, whereas there was no significant difference at the two articulation points without tongue involvement.

The Connected Critical Node Problem

The Critical Node Problem is a well-known optimisation problem that aims to find the subset of nodes in a graph whose removal impacts the graph connectivity as much as possible according to a specific connectivity measure. In this work, we study a new version of the Critical Node Problem, which we call the Connected Critical Node Problem, where the set of the removed nodes has to form a connected subgraph. We consider three connectivity measures and provide complexity results and solution approaches for general graphs and specific classes of graphs such as graphs with bounded treewidth, trees and series-parallel graphs. We consider the Connected Critical Node Problem where the pairwise connectivity (related to the number of pairs of vertices still connected in the graph) is minimised. We prove that this problem is strongly NP-hard and inapproximable on general graphs and is polynomial-time solvable on graphs with bounded treewidth and with unit connection costs. Further, we prove the NP-hardness of the problem with arbitrary connection costs over trees and series-parallel graphs and derive dynamic programming algorithms. We extend our results to the problem variants that consider the minimisation of the largest connected component and the maximisation of the number of connected components (also called K-way Vertex Cut Problem). As side results, we provide new complexity results for the classic Critical Node Problem on series-parallel graphs.

Examination of buyer perspectives and attitudes in relation to online shopping

Internet buying is widely recognized and regarded as a smart, advantageous, and open method of shopping. Organizations are investing much in research and development in order to make the Internet a viable retail channel. There isn't a single thing, service, or product that isn't available for purchase on the internet. In India, web-based shopping is growing at a rapid pace. The epidemic serves as a sort of articulation point for India's ecommerce industry, as more consumers are now able to purchase online. Customers all across the world are being persuaded to choose online buying over traditional commerce because of an outstandingly attractive lifestyle. Internet commerce is being pushed forward by a more established foundation, faster online speeds, and more PC knowledge. Many companies are entering this market and taking the competition seriously. The focus of the study focuses on customer perceptions of online purchasing. With the help of a poll, the investigation is focused on the most important facts.