Hierarchical Tree Method Research Articles

An Investigation of Fiat Characterization and Evolutionary Dynamics of the Cryptocurrency Market

Recent developments in global financial markets revealed that cryptocurrencies experienced rapid growth due to the popularity of blockchain technology and its evolving position in the digital finance industry. The rise of cryptocurrencies led economists to question generally accepted financial practices. Particularly the interaction between two different types of financial markets arose as a hot research topic to discover specific relationships and differences between major cryptocurrencies and fiat currencies. Therefore, this article aims to examine analyze by attaching importance to the Bitcoin to investigate significant linkages and analyze critical direct and indirect connections. In this research, Bitcoin—which is known as the most prominent cryptocurrency on the market—and 50 different conventional currencies are taken into consideration by applying cross-correlation, HT (hierarchical tree), and MST (minimum spanning tree) methods. The results of this work can be utilized by academicians and economists for further research related to the subject.

Chinese Shallow Semantic Parsing Based on Multi-method of Machine Learning

With the rapid development of 5G+ information intelligence, higher requirements are put forward for accurate and efficient semantic annotation methods. Semantic role annotation for any single method at present has its obvious and complementary advantages and disadvantages. Therefore, this paper attempts to introduce the above three mainstream and stable annotation methods into each task of semantic role annotation, and designs a Chinese semantic role annotation that integrates multi-method. This method integrates the statistical-based linear sequence method, the rule-based hierarchical tree method and the most advanced deep learning in the four processing modules of semantic role annotation. Multi-level linguistic features are introduced into the feature arrangement of the model to realize the mutual combination of multiple modules. Experiments show that the modular fusion of steps and methods effectively improves the annotation performance of each step of annotation.

Anti-NMDA Receptor Encephalitis: Efficacy of Treatment for Male Patients and miRNA Biomarker.

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is an acute form of encephalitis. Treatments for the anti-NMDA receptor encephalitis usually include steroids, intravenous immunoglobulin, plasma exchange, plasmapheresis, rituximab, cyclophosphamide and tumor resection. We aimed to compare the efficacy of the treatments including intravenous immunoglobulin, plasma exchange, plasmapheresis, rituximab or cyclophosphamide for male anti- NMDA receptor encephalitis patients without tumor and to discuss potential biomarkers for this disease. The Fisher exact test and the contingency table analysis were used to analyze the treatment efficacy for 43 male and 76 female patients. In addition, a hierarchical tree method was adopted to analyze the difference in the treatment efficacy between male and female patients. The p-values of testing whether the efficacy rate of plasmapheresis (or plasma exchange) for the male patient is greater than a threshold are significantly different from the pvalues for the other two treatments. In addition, the hierarchical tree method shows that the treatment strategy associating with early recovery is different for male and female patients. The results revealed that the efficacy rate of plasmapheresis (or plasma exchange) is not inferior to that of intravenous immunoglobulin and rituximab (or cyclophosphamide) for male patients without tumor. In addition, B-cell attracting C-X-C motif chemokine 13 (CXCL13) and microRNA let-7b have the potential to be the treatment response biomarkers for anti-NMDA receptor encephalitis. They may not be useful prognostic biomarkers for this encephalitis unless they are not biomarkers for other autoimmune encephalitides.

THE APPLICATION OF A HIERARCHICAL TREE METHOD TO ONTOLOGY KNOWLEDGE ENGINEERING

Ontology technologies have been widely studied for their capabilities of semantic description and knowledge inference in a variety of application domains. The main obstacle for the advancement of ontologies is the immature building methods and construction principles. It is challenging to discover how to tune a large complete ontology to small applications and build domain ontologies pragmatically. This paper proposes a hierarchical tree method that provides guidelines to the building of a hierarchical geo-ontology and corresponding construction rules for different levels of ontologies. This hierarchical ontology construction method can be used to realize lower-level ontology building based on the restrictions of the upper-level ontology. It can also connect different levels of ontologies into a hierarchical structure. Based on the resulting hierarchical tree structure, the management and usage of ontologies becomes feasible and more efficient. Furthermore, to better elaborate the hierarchical relationships among the concepts surrounding the basic tree structure, this paper introduces Class Meta-Information (CMI) to OWL (Ontology Web Language) and uses Hierarchical Identification (HID) to draw conclusion on concepts' hierarchical relations. Examples, experimental simulation and comparative analyses are given to explain further the applications of this hierarchical tree method in the areas of ontology engineering.

Complexity of major UK companies between 2006 and 2010: Hierarchical structure method approach

This study reports on topology of the top 40 UK companies that have been analysed for predictive verification of markets for the period 2006–2010, applying the concept of minimal spanning tree and hierarchical tree (HT) analysis. Construction of the minimal spanning tree (MST) and the hierarchical tree (HT) is confined to a brief description of the methodology and a definition of the correlation function between a pair of companies based on the London Stock Exchange (LSE) index in order to quantify synchronization between the companies. A derivation of hierarchical organization and the construction of minimal-spanning and hierarchical trees for the 2006–2008 and 2008–2010 periods have been used and the results validate the predictive verification of applied semantics. The trees are known as useful tools to perceive and detect the global structure, taxonomy and hierarchy in financial data. From these trees, two different clusters of companies in 2006 were detected. They also show three clusters in 2008 and two between 2008 and 2010, according to their proximity. The clusters match each other as regards their common production activities or their strong interrelationship. The key companies are generally given by major economic activities as expected. This work gives a comparative approach between MST and HT methods from statistical physics and information theory with analysis of financial markets that may give new valuable and useful information of the financial market dynamics.

Clusters Analyses in Regional Statistics

The concept of cluster is related to the spatial density of the economic organizations suggesting that there are some specialized industrial activities with a high degree of geographic concentration. Interdependent relations are developed among economic organizations included in the cluster, that lead to an increased labour productivity, enhancing their competitiveness on the market and the competitiveness of the area where they operate. The statistical cluster analysis uses the method of minimum dispersion of hierarchical tree method, in order to obtain the information necessary to small and medium organizations and the regeneration of some declining areas or industries. Territorial profile economic analyses can use the cluster analysis in order to make hierarchical classifications, according to performance, strategies. The hierarchical tree methods consist in identifying certain hierarchies used to take into consideration the units. According to their organization mode, clusters can be: vertically integrated, horizontally integrated, emerging clusters.

Numerical study of magneto-optical traps through a hierarchical tree method

We approach the problem of N atoms in a magneto-optical trap through a hierarchical tree method, using an algorithm originally developed by Barnes and Hut (BH) in the astrophysical context. Such an algorithm numerically takes care of the particle-particle interaction by controlling the approximation level in a way that offers more physical fidelity than the mean-field treatment and considerably less time consumption ({tau}{approx}N log{sub 10} N in the hierarchical BH method, in contrast with the {tau}{approx}N{sup 2} and {tau}{approx}N{sup 3/2} dependences found in direct and mean-field approaches, respectively). Our results reproduce the experimentally reported single-ring orbital mode for N < or approx. 10{sup 6} atoms and also find indication of a double-ring structure for N{approx}10{sup 7}, a situation mimicked by a N=10{sup 6} system with enhanced radiative force, in agreement with experimental observations. We stress that this high-density regime is not accessed by direct integration of the equations of motion, due to the enormous computing times required, and is not suitably described through mean-field approaches, due to the rather unphysical enhancement of the particle-particle interactions and the presence of a spurious numerical grid dependence.

Simulation of particle motions in an acoustophoresis device

Particles in a liquid host can be continuously fractionated by combining a laminar flow with an ultrasonic standing wave oriented perpendicular to the flow direction. This kind of separation method can separate particles based on their relative compressibilities as well as on mass density and size. Experimental work has focused on separating particles ranging in size from 5 to 55 μm in resonant devices operating from 100 kHz to 1 MHz. A numerical simulation based on a hierarchical tree method has been developed to simulate particle motion in such a device. The flow field, primary acoustic forces, and secondary interparticle acoustic forces are all taken into account. Full three-dimensional simulations can be performed. This method may be useful in other application areas where large numbers of particles, drops, and/or bubbles are under the influence of acoustic forces. [Work supported by NASA through Grant No. NAG8-1351.]

Cosmological Simulations with TreeSPH

We describe numerical methods for incorporating gas dynamics into cosmological simulations and present illustrative applications to the cold dark matter (CDM) scenario. Our evolution code, a version of TreeSPH (Hernquist \& Katz 1989) generalized to handle comoving coordinates and periodic boundary conditions, combines smoothed--particle hydrodynamics (SPH) with the hierarchical tree method for computing gravitational forces. The Lagrangian hydrodynamics approach and individual time steps for gas particles give the algorithm a large dynamic range, which is essential for studies of galaxy formation in a cosmological context. The code incorporates radiative cooling for an optically thin, primordial composition gas in ionization equilibrium with a user-specified ultraviolet background. We adopt a phenomenological prescription for star formation that gradually turns cold, dense, Jeans-unstable gas into collisionless stars, returning supernova feedback energy to the surrounding medium. In CDM simulations, some of the baryons that fall into dark matter potential wells dissipate their acquired thermal energy and condense into clumps with roughly galactic masses. The resulting galaxy population is insensitive to assumptions about star formation; we obtain similar baryonic mass functions and galaxy correlation functions from simulations with star formation and from simulations without star formation in which we identify galaxies directly from the cold, dense gas.

A microlensing model for QSO 2237 + 0305

Models of microlensing are presented for the four images of QSO 2237 + 0305, with the surface mass density and shear for each image based on the macrolensing model developed by Schneider et al. (1988). The computations were done with a new code that makes use of the hierarchical tree method. The high efficiency of this approach makes it possible to include up to 60,000 lensing stars with different masses. Examples are given of amplification maps, light curves, correlation functions, and amplification probabilities. All these are very strongly affected by the shear due to macrolensing. The observed changes in the luminosity of the four images of QSO 2237 + 0305 are most likely induced by microlensing. 16 refs.

Are some N-body algorithms intrinsically less collisional than others?

view Abstract Citations (82) References (33) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Are Some N-Body Algorithms Intrinsically Less Collisional than Others? Hernquist, Lars ; Barnes, Joshua E. Abstract Empirical tests are used to measure relaxation rates in direct summation, hierarchical tree, and spherical harmonic N-body codes. We find that these methods suffer from comparable levels of relaxation for the same particle number and effective spatial resolution. This conclusion is counter to the wide-spread belief that expansion techniques are intrinsically less collisional than other methods. In fact, any algorithm which represents the density field using discrete particles will be subject to fluctuations in the potential, resulting in departures from the mean-field limit. Given appropriate resources, direct summation and hierarchical tree methods are valid approaches for simulating collisionless systems. The suitability of a given technique for studying collisionless processes is determined only by considerations of efficiency. Publication: The Astrophysical Journal Pub Date: February 1990 DOI: 10.1086/168343 Bibcode: 1990ApJ...349..562H Keywords: Astronomical Models; Many Body Problem; Stellar Motions; Algorithms; Computational Astrophysics; Astrophysics; NUMERICAL METHODS; STARS: STELLAR DYNAMICS full text sources ADS |

TREESPH - A unification of SPH with the hierarchical tree method

view Abstract Citations (924) References (48) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS TREESPH: A Unification of SPH with the Hierarchical Tree Method Hernquist, Lars ; Katz, Neal Abstract A new, general-purpose code for evolving three-dimensional, self-gravitating fluids in astrophyics, both with and without collisionless matter, is described. In this TREESPH code, hydrodynamic properties are determined using a Monte Carlo-like approach known as smoothed particle hydrodynamics (SPH). Unlike most previous implementations of SPH, gravitational forces are computed with a hierarchical tree algorithm. Multiple expansions are used to approximate the potential of distant groups of particles, reducing the cost per step. More significantly, the improvement in efficiency is achieved without the introduction of a grid. A unification of SPH with the hierarchical tree method is a natural way of allowing for larger N within a Lagrangian framework. The data structures used to manipulate the grouping of particles can be applied directly to certain aspects of the SPH calculation. Publication: The Astrophysical Journal Supplement Series Pub Date: June 1989 DOI: 10.1086/191344 Bibcode: 1989ApJS...70..419H Keywords: Computational Fluid Dynamics; Computerized Simulation; Data Smoothing; Magnetohydrodynamics; Trees (Mathematics); Dynamical Systems; Many Body Problem; Monte Carlo Method; Spatial Resolution; Fluid Mechanics and Heat Transfer; HYDRODYNAMICS; NUMERICAL METHODS full text sources ADS |

Cosmological simulations using the hierarchical tree method

view Abstract Citations (52) References (20) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Cosmological Simulations Using the Hierarchical Tree Method Bouchet, Francois R. ; Hernquist, Lars Abstract Simulations are used here to show that the hierarchical tree method can faithfully reproduce the statistical behavior of systems undergoing clustering through gravitational instability. The influence of the approximation in the potential, the two-body softening length, the time-step, and the particle number on the resulting evolution is investigated in order to infer the properties of the method for future applications. Various schemes for handling boundary conditions are briefly discussed. It is shown that the efficiency of the technique is insensitive to the degree of clustering present in the simulations. Hence, the hierarchical tree method may be superior to more traditional N-body algorithms for evolving strongly nonlinear systems requiring a large particle number and dynamical range. Publication: The Astrophysical Journal Supplement Series Pub Date: December 1988 DOI: 10.1086/191299 Bibcode: 1988ApJS...68..521B Keywords: Computerized Simulation; Galactic Clusters; Hubble Constant; Many Body Problem; Trees (Mathematics); Boundary Conditions; Boundary Value Problems; Dark Matter; Hierarchies; Astrophysics; COSMOLOGY; GALAXIES: CLUSTERING; NUMERICAL METHODS full text sources ADS |

Hierarchical N-body methods

The hierarchical tree method offers the possibility of computing the interaction between N self-gravitating particles in a time ≈ 0 ( N log N), without using a grid. The potential advantages of this technique for collisionless systems and for particle hydrodynamic schemes are discussed.