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New MDS or Near-MDS Self-Dual Codes
Gulliver, T.A.,Jon-Lark Kim,Yoonjin Lee IEEE 2008 IEEE transactions on information theory Vol.54 No.9
<P>We construct new MDS or near-MDS self-dual codes over large finite fields. In particular, we show that there exists a Euclidean self-dual MDS code of length n = q over GF(q) whenever q = 2<SUP>m</SUP> (m ges 2) using a Reed-Solomon (RS) code and its extension. It turns out that this multiple description source (MDS) self-dual code is an extended duadic code. We construct Euclidean self-dual near-MDS codes of length n = q-1 over GF(q) from RS codes when q = 1 (mod 4) and q les 113. We also construct many new MDS self-dual codes over GF(p) of length 16 for primes 29 les p les 113. Finally, we construct Euclidean/Hermitian self-dual MDS codes of lengths up to 14 over GF(q<SUP>2</SUP>) where q = 19, 23,25, 27, 29.</P>
REGULARITY OF SOAP FILM-LIKE SURFACES SPANNING GRAPHS IN A RIEMANNIAN MANIFOLD
Gulliver, Robert,Park, Sung-Ho,Pyo, Jun-Cheol,Seo, Keom-Kyo Korean Mathematical Society 2010 대한수학회지 Vol.47 No.5
Let M be an n-dimensional complete simply connected Riemannian manifold with sectional curvature bounded above by a nonpositive constant $-{\kappa}^2$. Using the cone total curvature TC($\Gamma$) of a graph $\Gamma$ which was introduced by Gulliver and Yamada [8], we prove that the density at any point of a soap film-like surface $\Sigma$ spanning a graph $\Gamma\;\subset\;M$ is less than or equal to $\frac{1}{2\pi}\{TC(\Gamma)-{\kappa}^2Area(p{\times}\Gamma)\}$. From this density estimate we obtain the regularity theorems for soap film-like surfaces spanning graphs with small total curvature. In particular, when n = 3, this density estimate implies that if $TC(\Gamma)$ < $3.649{\pi}\;+\;{\kappa}^2\inf\limits_{p{\in}F}Area(p{\times}{\Gamma})$, then the only possible singularities of a piecewise smooth (M, 0, $\delta$)-minimizing set $\Sigma$ are the Y-singularity cone. In a manifold with sectional curvature bounded above by $b^2$ and diameter bounded by $\pi$/b, we obtain similar results for any soap film-like surfaces spanning a graph with the corresponding bound on cone total curvature.
REGULARITY OF SOAP FILM-LIKE SURFACES SPANNING GRAPHS IN A RIEMANNIAN MANIFOLD
Robert Gulliver,박성호,표준철,서검교 대한수학회 2010 대한수학회지 Vol.47 No.5
Let M be an n-dimensional complete simply connected Riemannian manifold with sectional curvature bounded above by a nonpositive constant −κ2. Using the cone total curvature TC(Γ) of a graph ¡ which was introduced by Gulliver and Yamada [8], we prove that the density at any point of a soap film-like surface Σ spanning a graph ¡ Γ M is less than or equal to [수식]. From this density estimate we obtain the regularity theorems for soap film-like surfaces spanning graphs with small total curvature. In particular, when n = 3,this density estimate implies that if [수식] then the only possible singularities of a piecewise smooth (M, 0, δ)-minimizing set Σ are the Y -singularity cone. In a manifold with sectional curvature bounded above by b2 and diameter bounded by π/b, we obtain similar results for any soap film-like surfaces spanning a graph with the corresponding bound on cone total curvature.
Bubble size characteristics in the wake of ventilated hydrofoils with two aeration configurations
John S Gulliver,Ashish Karn,Christopher R Ellis,Christopher Milliren,Jiarong Hong,David Scott,Roger E.A. Arndt 한국유체기계학회 2015 International journal of fluid machinery and syste Vol.8 No.2
Aerating hydroturbines have recently been proposed as an effective way to mitigate the problem of low dissolved oxygen in the discharge of hydroelectric power plants. The design of such a hydroturbine requires a precise understanding of the dependence of the generated bubble size distribution upon the operating conditions (viz. liquid velocity, air ventilation rate, hydrofoil configuration, etc.) and the consequent rise in dissolved oxygen in the downstream water. The purpose of the current research is to investigate the effect of location of air injection on the resulting bubble size distribution, thus leading to a quantitative analysis of aeration statistics and capabilities for two turbine blade hydrofoil designs. The two blade designs differed in their location of air injection. Extensive sets of experiments were conducted by varying the liquid velocity, aeration rate and the hydrofoil angle of attack, to characterize the resulting bubble size distribution. Using a shadow imaging technique to capture the bubble images in the wake and an in-house developed image analysis algorithm, it was found that the hydrofoil with leading edge ventilation produced smaller size bubbles as compared to the hydrofoil being ventilated at the trailing edge.
OPTIMAL LINEAR CODES OVER ℤ<sub>m</sub>
Dougherty, Steven T.,Gulliver, T. Aaron,Park, Young-Ho,Wong, John N.C. Korean Mathematical Society 2007 대한수학회지 Vol.44 No.5
We examine the main linear coding theory problem and study the structure of optimal linear codes over the ring ${\mathbb{Z}}_m$. We derive bounds on the maximum Hamming weight of these codes. We give bounds on the best linear codes over ${\mathbb{Z}}_8$ and ${\mathbb{Z}}_9$ of lengths up to 6. We determine the minimum distances of optimal linear codes over ${\mathbb{Z}}_4$ for lengths up to 7. Some examples of optimal codes are given.
Unsupervised Log Message Anomaly Detection
Amir Farzad,T. Aaron Gulliver 한국통신학회 2020 ICT Express Vol.6 No.3
Log messages are now broadly used in cloud and software systems. They are important for classification and anomaly detection as millions of logs are generated each day. In this paper, an unsupervised model for log message anomaly detection is proposed which employs Isolation Forest and two deep Autoencoder networks. The Autoencoder networks are used for training and feature extraction, and then for anomaly detection, while Isolation Forest is used for positive sample prediction. The proposed model is evaluated using the BGL, Openstack and Thunderbird log message data sets. The results obtained show that the number of negative samples predicted to be positive is low, especially with Isolation Forest and one Autoencoder. Further, the results are better than with other well-known models.
Joint TAS and Power Allocation for IHDAF Relaying M2M Cooperative Networks
( Lingwei Xu ),( Hao Zhang ),( T. Aaron Gulliver ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.5
The outage probability (OP) performance of multiple-relay-based incremental hybrid decode-amplify-forward (IHDAF) relaying mobile-to-mobile (M2M) networks with transmit antenna selection (TAS) over N-Nakagami fading channels is investigated in this paper. The closed-form expressions for approximate OP of the optimal and suboptimal TAS schemes are derived. The power allocation problem is formulated for performance optimization. Then the OP performance under different conditions is evaluated through numerical simulations to verify the analysis. The simulation results showed that optimal TAS scheme has a better OP performance than suboptimal TAS scheme; the power-allocation parameter has an important influence on the OP performance.
Energy Detector based Time of Arrival Estimation using a Neural Network with Millimeter Wave Signals
( Xiaolin Liang ),( Hao Zhang ),( T. Aaron Gulliver ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.7
Neural networks (NNs) are extensively used in applications requiring signal classification and regression analysis. In this paper, a NN based threshold selection algorithm for 60 GHz millimeter wave (MMW) time of arrival (TOA) estimation using an energy detector (ED) is proposed which is based on the skewness, kurtosis, and curl of the received energy block values. The best normalized threshold for a given signal-to-noise ratio (SNR) is determined, and the influence of the integration period and channel on the performance is investigated. Results are presented which show that the proposed NN based algorithm provides superior precision and better robustness than other ED based algorithms over a wide range of SNR values. Further, it is independent of the integration period and channel model.
Relay Selection in the DF Relaying M2M Cooperative Networks
Lingwei Xu,Hao Zhang,T .Aaron Gulliver 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.1
The outage probability (OP) and average symbol error probability (ASEP) performance of multiple-mobile-relay-based mobile-to-mobile (M2M) networks with decode-and-forward (DF) relaying over N-Nakagami fading channels is investigated in this paper. The power allocation problem is formulated to determine how the overall transmit power should be shared between broadcasting and relaying phases for performance optimization. Then the OP and ASEP performance under different conditions is evaluated through numerical simulations to verify the analysis. The simulation results show that the fading coefficient, the number of cascaded components, the relative geometrical gain, the power-allocation parameter, and the number of mobile relays have an important influence on the OP and ASEP performance.