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1

Proof of Multicopy via Proof of File Position in Cloud

Zhang H., Cao Z., Dong X., Shen J.

Fundamenta Informaticae

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2018

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Vol. 157, nr 1/2

141--151

EN

For disaster recovery, we store backups of a file in several positions far away from each other. If we delegate this task to an untrusted cloud service provider, a verification method is desired. In this paper, we construct a generic transformation from “proof of retrievability” to “proof of multicopy”. We present this work in two stages. In the first stage, we propose a generic protocol of “proof of file position” based on an arbitrary secure “proof of retrievability” protocol. In the second stage, we propose a “proof of multicopy” protocol based on our “proof of file position” protocol. Both of our protocols are provably secure.

2

Comparison of 2D and 3D models of salinity numerical simulation

Li C., Pan X., Ke J., Dong X.

Polish Maritime Research

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2015

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S 1

26--29

EN

For the study of the effect of 2D and 3D mathematical model in salinity simulation, with Liuheng island strong brine discharge of seawater desalination project as an example, using 2D and 3D salinity mathematical models of Liuheng island to simulate coastal hydrodynamic environment and salinity distribution before and after the concentrated brine discharge, and analyzed the results. Finally got the applicable scope of the two models, it has an important significance in the study of similar problems.

3

Estymacja parametrów składowej podstawowej prądu wtórnego przekładnika prądowego odkształconego na skutek nasycenia rdzenia magnetycznego

Bąk D., Dong X., Rebizant W.

Przegląd Elektrotechniczny

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2014

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R. 90, nr 3

46--49

PL

W artykule przedstawiono nowy algorytm do estymacji parametrów składowej podstawowej sygnału prądu wtórnego przekładnika prądowego zniekształconego na skutek nasycenia rdzenia magnetycznego. Opisywany algorytm został zaprojektowany przy użyciu innowacyjnej, metodologii, w której pobrane próbki prądu wtórnego traktowane są jako współrzędne wektora umieszczonego w trójwymiarowej przestrzeni. Badania symulacyjne wykonane z wykorzystaniem ATP/EMTP potwierdzają dużą skuteczność proponowanego algorytmu.

EN

In the paper a new algorithm is described that is intended for estimation of fundamental component parameters of the distorted secondary CT current due to magnetic core saturation. The algorithm presented was derived with use of the innovative methodology where the current samples measured are treated as components of three-dimensional space vector. Simulative investigations with use of ATP/EMTP package confirm high efficiency of the proposed algorithm.

4

Focus shaping of Weierstrass solid immersion lens by an axisymmetric Bessel-modulated Gaussian beam

Dong X., Geng T., Zhuang S.

Optica Applicata

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2013

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Vol. 43, nr 2

s. 247--259

EN

Weierstrass solid immersion lens (SIL) has been used to obtain superresolution because a smaller focal size is desirable. In this paper, focus shaping of Weierstrass SIL illuminated by an axisymmetric Bessel-modulated Gaussian beam (QBG beam) is investigated. It has been found theoretically that the sharper focusing of Weierstrass SIL disappears for a certain beam order of QBG beam. For case of a smaller beam order, the focus still locates on the plane of Weierstrass SIL and Weierstrass SIL still plays a tighter focusing role. However, when the beam order increases continuously, the focus lefts the plane of Weierstrass SIL, and shifts along an optical axis considerably. In addition, under condition of the higher beam order, the dependence of the focal shift on the beam order is nearly linear, which may be used to alter a focal position conveniently.

5

New method of CT saturation detection

Bąk D., Dong X., Rebizant W.

Present Problems of Power System Control

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2012

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Nr 2

65-72

EN

A new method for detection of CT saturation is presented in this paper. The presented algorithm applies a new, innovative methodology mapping first order derivative of phase current signals into coordinates of a 3D vector. The comparison of proposed algorithm with standard one based on secondary current signal's second derivative is conducted and some of simulation results are presented to show the proposed algorithm effectiveness.

6

Focus shaping of Bessel-Gauss beam with radial varying polarization

Gao X., Fu R., Shen H., Dong X., Geng T., Zhuang S.

Optica Applicata

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2012

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Vol. 42, nr 3

481-491

EN

Focusing properties of Bessel-Gauss beam with radial varying polarization are investigated based on vector diffraction theory in this article. The polarization angle formed by polarization direction and radial coordinate is the function of the radial distance in pupil plane, and one polarization parameter indicates the speed of change of polarization angle. It was found that the intensity distribution in focal region can be altered considerably by the beam parameter and polarization parameter. For a small beam parameter, the focal spot broadens transversely, distorts into ring focus, and then evolves back into focal spot on increasing polarization parameter. When beam parameter gets higher, focal pattern becomes complicated and the focus evolution principle with increasing beam parameter also changes significantly. Some novel focal patterns may appear, including multiple intensity rings, dark hollow focus, cylindrical crust focus.

7

Reaction kinetics and thiourea removal by ozone oxidation

Xie Q., Dong X., Huang W., Xu H., Du H.

Environment Protection Engineering

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2012

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Vol. 38, nr 4

87--98

EN

Thiourea is a toxicant which will bring some adverse effects to the public health. In the study, thiourea was degraded via ozonation process. The results show that the ozonation is an effective method to remove thiourea from wastewaters. When the ozone flow rate was 600 cm3*min-1, pH was 7.3, the temperature was 20 °C, 93.97% of thiourea (200 cm3 solution of 3 g dm-3) could be degraded after 9 min of reaction. The reaction order of ozonation of thiourea n was 0.11, and the reaction rate constant k = 0.4898 g0.89 (dm3)-0.89*min -1.

8

On nonlocal problems for fractional differential equations in Banach spaces

Dong X., Wang J., Zhou Y.

Opuscula Mathematica

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2011

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Vol. 31, no. 3

341-357

EN

In this paper, we study the existence and uniqueness of solutions to the nonlocal problems for the fractional differential equation in Banach spaces. New sufficient conditions for the existence and uniqueness of solutions are established by means of fractional calculus and fixed point method under some suitable conditions. Two examples are given to illustrate the results.

9

A New Practical Limited Identity-Based Encryption Scheme

Lu R., Cao Z., Dong X.

Fundamenta Informaticae

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2007

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Vol. 80, nr 4

461-474

EN

Identity based cryptography was introduced by Shamir in 1984, which avoids the trust problems encountered in the traditional Public Key Infrastructures. After Boneh and Franklin proposed the first full functional identity based encryption scheme from the bilinear pairings in 2001, many other identity based schemes using pairings have been proposed. However, how to design a practical identity based encryption scheme that avoids using the pairings is still an open problem today. In this paper, after studying and combining the advantages of the traditional public key system and identity based system, we formally define a new Limited identity based system and present a concrete Limited identity based encryption scheme on a different complexity assumption. The resulting scheme is not only provably secure against the chosen plaintext attack in the random oracle, but also especially suitable for some practical system, such as an email system.