• Nuclear Engineering and Technology
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• v.12 no.4
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• pp.286-292
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• 1980

Similitude requirement for model testing of flow induced vibration of reactor internals are investigated. In depth discussions on the Reynolds number effects are made. For valid model tests of fuel assemblies vibrating in its fundamental natural frequency, reduced frequency (fD/U), and dam ping parameter( $m_{c}$$\delta$$_{c}$ $D_{\rho}$$^2$) are two most important parameters.ers.

• Journal of applied mathematics & informatics
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• v.8 no.2
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• pp.361-370
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• 2001

Testing equality of covariance matrix of k populations has long been an interesting issue in statistical inference. To overcome the sparseness of data points in a high-dimensional space and deal with the general cases, we suggest several projection pursuit type statistics. Some results on the limiting distributions of the statistics are obtained. some properties of Bootstrap approximation are investigated. Furthermore, for computational reasons an approximation which is based on Number theoretic method for the statistics is adopted. Several simulation experiments are performed.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1293-1297
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• 2011

To improve the biological activities of rupestonic acid, 21 new rupestonic acid fatty ester derivatives (2a-2h) and aromatic ester derivatives (2i-2u) were synthesized and preliminarily evaluated for their anti-influenza activity in vitro by the national center for drug screening of China, using the Oseltamivir and Ribavirin as reference drugs. The results showed that 2l ($IC_{50}=0.5{\mu}mol/L$) exhibited potent anti-influenza $A_3$ viral activity among the synthesized compounds and was 10-fold more potent than that of the reference drug Oseltamivir ($IC_{50}=5.1{\mu}mol/L$).

• The Korean Journal of Ceramics
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• v.7 no.1
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• pp.11-15
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• 2001

A thermodynamic assessment for the ZrO$_2$-TiO$_2$ system has been conducted. An optimal thermodynamic data set for this system is evaluated by the CALPHAD(CALculation of PHAse Diagram) method applied to experimental phase diagram and thermodynamic data. The liquid is described by ionic liquid model with two sublattices. The solubilities of the solid phases, tetragonal ZrO$_2$ and TiO$_2$(rutile), were described by subregular substitutional model with one sublattice. Two compounds, ZrTiO$_4$ and ZrTi$_2$O$_6$, are modeled as stoichiometric compounds.

• Bulletin of the Korean Mathematical Society
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• v.48 no.2
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• pp.247-260
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• 2011

Let h be a meromorphic function with few poles and zeros. By Nevanlinna's value distribution theory we prove some new properties on the polynomials in h with the coefficients being small functions of h. We prove that if f is a meromorphic function and if $f^m$ is identically a polynomial in h with the constant term not vanish identically, then f is a polynomial in h. As an application, we are able to find the entire solutions of the differential equation of the type $$f^n+P(f)=be^{sz}+Q(e^z)$$, where P(f) is a differential polynomial in f of degree at most n-1, and Q($e^z$) is a polynomial in $e^z$ of degree k $\leqslant$ max {n-1, s(n-1)/n} with small functions of $e^z$ as its coefficients.

• Journal of the Korean Mathematical Society
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• v.48 no.6
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• pp.1225-1248
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• 2011

The present paper is concerned with a two-competitor/oneprey population system with Holling type-II functional response and two discrete delays. By linearizing the system at the positive equilibrium and analyzing the associated characteristic equation, the asymptotic stability of the positive equilibrium and existence of local Hopf bifurcations are investigated. Particularly, by applying the normal form theory and the center manifold reduction for functional differential equations (FDEs) explicit formulae determining the direction of bifurcations and the stability of bifurcating periodic solutions are derived. Finally, to verify our theoretical predictions, some numerical simulations are also included at the end of this paper.

• Journal of Korean Neurosurgical Society
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• v.55 no.2
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• pp.103-105
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• 2014

Intracranial haemorrhages are rare but potentially life-threatening complications of spine surgery. Most reported cases involved subdural or cerebellar haemorrhages; supratentorial parenchymal bleeding is very uncommon. We report a 28-year-old woman who underwent resection of a thoracic Ewing's sarcoma, and developed fatal haemorrhages around her cerebral metastases during surgery. The clinical presentations, possible pathogenesis and potential preventive measures are discussed. Patients with disseminated metastases within the neural axis are at risks of intracranial complications during spine surgery. The presence of intracranial mass lesions should be considered as a relative contraindication to intradural spine surgery.

• Journal of information and communication convergence engineering
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• v.9 no.5
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• pp.523-529
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• 2011

In this paper an inter-layer protocol, referred to as a Multi-Network Selector (MNS) is proposed for multiband maritime networks. A MNS is located between the data-link layer and the network layer and performs vertical handover when a ship moves another radio network. In order to provide seamless data transfer to different radio networks, the MNS uses received signal strength (RSS) and ship's location information as decision parameters for vertical handover, which can avoid ping-pong effect and reduces handover latency. In addition, we present related issues in order to implement the MNS for a multiband maritime network.

• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.64-70
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• 2010

In this paper, we study and develope a special secure Dongle to be adapted in GSM SmartPhone for secure voice communication to the serial 20-pin connector in SmartPhone. We design and implement the Dongle module hardware, firmware, and software including cipher crypto-synchronization and cipher algorithm. Also we study and emulate the SmartPhone GUI software interface including communication software module to the Dongle. Finally, we analyze the performances of crypto-synchronization in some noisy environment and also we test the secure Dongle module.

• Journal of Information Processing Systems
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• v.14 no.2
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• pp.377-395
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• 2018

Aiming at the problem of service reliability in resource reservation in cloud computing environments, a model of dynamic cloud resource reservation based on trust is proposed. A domain-specific cloud management architecture is designed in which resources are divided into different management domains according to the types of service for easier management. A dynamic resource reservation mechanism (DRRM) is used to test users' reservation requests and reserve resources for users. According to user preference, several resources are chosen to be candidate resources by fuzzy cluster analysis. The fuzzy evaluation method and a two-way trust evaluation mechanism are adopted to improve the availability and credibility of the model. An analysis and simulation experiments show that this model can increase the flexibility of resource reservation and improve user satisfaction.