4,069 research outputs found

    On computing joint invariants of vector fields

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    A constructive version of the Frobenius integrability theorem -- that can be programmed effectively -- is given. This is used in computing invariants of groups of low ranks and recover examples from a recent paper of Boyko, Patera and Popoyvich \cite{BPP}

    A secure data outsourcing scheme based on Asmuth – Bloom secret sharing

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Data outsourcing is an emerging paradigm for data management in which a database is provided as a service by third-party service providers. One of the major benefits of offering database as a service is to provide organisations, which are unable to purchase expensive hardware and software to host their databases, with efficient data storage accessible online at a cheap rate. Despite that, several issues of data confidentiality, integrity, availability and efficient indexing of users’ queries at the server side have to be addressed in the data outsourcing paradigm. Service providers have to guarantee that their clients’ data are secured against internal (insider) and external attacks. This paper briefly analyses the existing indexing schemes in data outsourcing and highlights their advantages and disadvantages. Then, this paper proposes a secure data outsourcing scheme based on Asmuth–Bloom secret sharing which tries to address the issues in data outsourcing such as data confidentiality, availability and order preservation for efficient indexing

    Gamma flashes from relativistic electron-positron plasma droplets

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    Ultra-intense lasers are expected to produce, in near future, relativistic electron-positron plasma droplets. Considering the local photon production rate in complete leading order in quantum electrodynamics (QED), we point out that these droplets are interesting sources of gamma ray flashesComment: 4 pages, 6 figures; Text has been revised and new refs. are adde

    Non-Hermitian von Roos Hamiltonian's η\eta-weak-pseudo-Hermiticity, isospectrality and exact solvability

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    A complexified von Roos Hamiltonian is considered and a Hermitian first-order intertwining differential operator is used to obtain the related position dependent mass η\eta-weak-pseudo-Hermitian Hamiltonians. Using a Liouvillean-type change of variables, the η\eta-weak-pseudo-Hermitian von Roos Hamiltonians H(x) are mapped into the traditional Schrodinger Hamiltonian form H(q), where exact isospectral correspondence between H(x) and H(q) is obtained. Under a user-friendly position dependent mass settings, it is observed that for each exactly-solvable η\eta-weak-pseudo-Hermitian reference-Hamiltonian H(q)there is a set of exactly-solvable η\eta-weak-pseudo-Hermitian isospectral target-Hamiltonians H(x). A non-Hermitian PT-symmetric Scarf II and a non-Hermitian periodic-type PT-symmetric Samsonov-Roy potentials are used as reference models and the corresponding η\eta-weak-pseudo-Hermitian isospectral target-Hamiltonians are obtained.Comment: 11 pages, no figures

    A New Extension of Power Hazard Distribution with Applications

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    A new lifetime distribution is suggested using the Sine function by considering power hazard distribution as baseline distribution. Some mathematical and statistical features are discussed. The Maximum likelihood method is used to estimate the parameters for proposed distribution. Three real data sets are examined to analyze the performance of proposed distribution with some other distributions. The new distribution has been shown better fit to the bladder cancer patients’ data and COVID-19 data as compared to some distributions through statistical criterion

    The Energy Eigenvalues of the Two Dimensional Hydrogen Atom in a Magnetic Field

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    In this paper, the energy eigenvalues of the two dimensional hydrogen atom are presented for the arbitrary Larmor frequencies by using the asymptotic iteration method. We first show the energy eigenvalues for the no magnetic field case analytically, and then we obtain the energy eigenvalues for the strong and weak magnetic field cases within an iterative approach for n=210n=2-10 and m=01m=0-1 states for several different arbitrary Larmor frequencies. The effect of the magnetic field on the energy eigenvalues is determined precisely. The results are in excellent agreement with the findings of the other methods and our method works for the cases where the others fail.Comment: 13 pages and 5 table

    Characterization of LUSI Mud as Geopolymer Raw Material

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    The mud of mud volcano samples were collected from an eruption site named ‘LUSI’ (Lumpur “mud” –Sidoarjo), East Java, Indonesia for characterization. Analysis showed that, the major constituents of mud are SiO2 and Al2O3 which are higher than those in fly ash. The particle of mud has a flake-shaped particle and the overall particle size is dominated by particles between 2.5μm – 25.0μm. The results of XRD shows that mud of mud volcano have a characteristic of structurally disordered compounds, and a set of peaks corresponding to minor crystalline phases such as quartz, feldspars, and kaolinite. FTIR adsorption bands of the raw material of mud have the chemical bonding between bands 1-5

    Surface Tension at Finite Tempearture in the MIT Bag Model

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    At T=0 T = 0 the surface tension σ1/3 \sigma ^{1/3} in the MIT bag model for a single hadron is known to be negligible as compared to the bag pressure B1/4 B^{1/4}. We show that at finite temperature it has a substantial value of 50 - 70 MeV which also differ from hadron to hadron. We also find that the dynamics of the Quark-Gluon Plasma is such that the creation of hybrids (ssˉg)(s\bar{s}g) with massive quarks will predominate over the creation of (ssˉ) (s\bar{s}) mesons.Comment: Substantial changes in the revised version and a new author included, 13 pages in Latex and one figur

    Government Fiscal Policy Impact Analysis in Infrastructure Sector and Education Sector to Improve Public Welfare

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    This study aimed to conduct a study and analysis of government fiscal policies related to the components of revenue (taxes) and some components of spending (education/human resources and infrastructure sectors). Issues regarding the effectiveness of the allocation of government budgets, particularly for human resources and infrastructure sectors, is an important issue that is very interesting to discuss. Especially if associated with their impact on improving people\u27s welfare. With a limited income, the government must make a choice to prioritize the education/human resources sector or infrastructure sector
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