Wyniki wyszukiwania - Biblioteka Nauki

1

On existence of subharmonic orbits in perturbed Hamiltonian systems

100%

Yang X.

Bulletin of the Polish Academy of Sciences. Mathematics

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2000

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tom Vol. 48, no 2

221--225

EN

In this paper the existence of subharmonic orbits in planar Hamiltonian system x = f(x) + [epsilon]g(x,t) is revisited. The existing error in treatment on this problem is discussed and a new rigorous treatment is given.

2

Vector operation of one-cycle controlled matrix rectifier

71%

Yang X. , Jiang J. , Yang X.

Archives of Electrical Engineering

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2012

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tom Vol. 61, nr 2

149-164

EN

In the paper an algorithm and computer code for the identification of the hysteresis parameters of the Jiles-Atherton model have been presented. For the identification the particle swarm optimization method (PSO) has been applied. In the optimization procedure five design variables has been assumed. The computer code has been elaborated using Delphi environment. Three types of material have been examined. The results of optimization have been compared to experimental ones. Selected results of the calculation for different material are presented and discussed. A novel vector operated one-cycle control matrix rectifier (OCC-MR) is proposed in this paper. Matrix rectifier (MR) is a generalized buck three-phase AC-DC converter with four-quadrant operation capability. MR can also be the front-stage circuit of AC-DC-AC equivalent structure of MC. One-cycle control (OCC) is a nonlinear control technique, which integrates modulation algorithm and control strategy. By applying OCC to current control loop, the OCC-MR achieves balance only in a switching cycle,and realizes unitary input power factor. Furthermore, vector operation of OCC results In minimum switching losses. In order to make up for the insufficiency of OCC on load disturbance suppression, a PID controller is added onto output voltage control to improve load regulation. The OCC-MR features great simplicity, fast dynamic response and good immunity on input disturbance. On the basis of theoretical analysis, a systematic simulation of OCC-MR is implemented by means of Matlab/Simulink. Both static state performance and dynamic state performance of OCC-MR are discussed deeply. The simulation results have proved theoretical analysis of the vector operation of OCC-MR, and the control effects are satisfactory.

3

Fault tolerant control using Gaussian processes and model predictive control

63%

Yang X. , Maciejowski J. M.

International Journal of Applied Mathematics and Computer Science

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2015

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tom Vol. 25, no. 1

133--148

EN

Essential ingredients for fault-tolerant control are the ability to represent system behaviour following the occurrence of a fault, and the ability to exploit this representation for deciding control actions. Gaussian processes seem to be very promising candidates for the first of these, and model predictive control has a proven capability for the second. We therefore propose to use the two together to obtain fault-tolerant control functionality. Our proposal is illustrated by several reasonably realistic examples drawn from flight control.

4

On the Insecurity of an Identity Based Proxy Re-encryption Scheme

63%

Wang X. A. , Yang X.

Fundamenta Informaticae

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2010

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tom Vol. 98, nr 2/3

277-281

EN

At Pairing'07, Matsuo proposed two proxy re-encryption schemes: proxy re-encryption fromCBE to IBE and IBE to IBE. Now both schemes have been standardized by P1363.3workgroup. In this paper, we show that their identity based proxy re-encryption scheme is insecure. We give two attacks to this scheme. The first attack shows that the proxy can re-encrypt any IBE user's ciphertext to be the delegatee's ciphertext. The second attack implies that, if the proxy colludes with any delegatee, the proxy and this delegatee can derive any other IBE user’s secret key.

5

Lycocerus strictipennis sp. nov. from Yunnan, China, the second species in the Michiakii species-group of Lycocerus Gorham (Coleoptera: Cantharidae)

63%

Yang Y. , Yang X.

Annales Zoologici

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2011

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tom 61

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nr 4

EN

A second species of michiakii species-group of Lycocerus Gorham is described, L. strictipennis sp. nov. (CHINA, Yunnan), and provided with illustrations of aedeagus. L. michiakii Okushima et Brancucci, 2008 is recorded from China for the first time. Habitus photos of both species are presented.

6

On the longest runs in Markov chains

63%

Liu Z. , Yang X.

Probability and Mathematical Statistics

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2018

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tom Vol. 38, Fasc. 2

407--428

EN

In the first n steps of a two-state (success and failure) Markov chain, the longest success run L(n) has been attracting considerable attention due to its various applications. In this paper, we study L(n) in terms of its two closely connected properties: moment generating function and large deviations. This study generalizes several existing results in the literature, and also finds an application in statistical inference. Our metod on the moment generating function is based on a global estimate of the cumulative distribution function of L(n) proposed in this paper, and the proofs of the large deviations include the Gärtner-Ellis theorem and the moment generating function.

7

Modelling Multi-agent Three-way Decisions with Decision-theoretic Rough Sets

63%

Yang X. , Yao J. T.

Fundamenta Informaticae

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2012

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tom Vol. 115, nr 2/3

157-171

EN

The decision-theoretic rough set (DTRS) model considers costs associated with actions of classifying an equivalence class into a particular region. With DTRS, one may make informative decisions in the form of three-way decisions. Current research mainly focuses on single agent DTRS which is too complex for making a decision when multiple agents are involved. We propose a multiagent DTRS model and express it in the form of three-way decisions. The new model seeks for synthesized or consensus decisions when there aremultiple decision preferences and criteria adopted by different agents. Various multi-agent DTRS models can be derived according to the conservative, aggressive and majority viewpoints based on the positive, negative and boundary regions made by each agent. These multi-agent decision regions are expressed by figures in the form of three-way decisions.

8

Representation of The Pairwise Comparisons in AHP Using Hesitant Cloud Linguistic Term Sets

63%

Huang H.-C. , Yang X.

Fundamenta Informaticae

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2016

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tom Vol. 144, nr 3/4

349--362

EN

The analytic hierarchy process (AHP) is the most popular extension to the pairwise comparisons method which is based on the observation that it is much easier to rank several objects when restricted to two objects at one time. As the pairwise comparisons are subjective, the use of linguistic expressions rather than numerical values is straightforward and friendlier due to the uncertainties that are inherent in human judgments. In this paper, to handle the uncertainty and hesitancy in practical decisionmaking situations, we represent pairwise comparisons in AHP using hesitant cloud linguistic term sets (HCLTSs) which are proposed based on hesitant fuzzy linguistic term sets (HFLTSs) and normal cloud models. Then, the synthetic cloud model aggregation algorithm is proposed to transform the HCLTS pairwise comparison matrix into the positive reciprocal synthetic cloud matrix. A prioritization method using the geometric mean technique is adopted, and the ranking method based on comparing of the parameters of normal cloud models is proposed. Thus, we extend the traditional AHP method in hesitant and uncertain environment, and we call it HCLTS-AHP method. The comparative linguistic expressions of preferences become more flexible and richer and are more similar to human beings’ cognitive models. Furthermore, the synthetic cloud model is consistent with objectivity and the calculations are easy to implement. An illustrated example is applied to the ranking of four alternatives to show the usefulness of the proposed HCLTS-AHP method.

9

Experimental and Numerical Simulation of the Tensile Behaviour of a Biaxial Warp-knitted Composite

51%

Gao X. , Yang X. , Li D. , Li Y.

Fibres & Textiles in Eastern Europe

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2018

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tom Vol. 26, no. 6 (132)

71--76

EN

In this paper a composite reinforced with biaxial warp-knitted fabric and epoxy resin was manufactured by applying vacuum assisted resin transfer moldings (VARTM). The quasi-static tensile behaviour was experimentally tested in 0° and 90° directions, respectively. A finite element model of biaxial warp-knitted composites was developed on a meso-scale. The tensile behaviour of the composites was numerical simulated and compared with the experimental results. It showed that there is an approximate agreement between experimental and numerical results. There are maximum errors sum of squares of 14.52% and 33.29%. The finite element model of biaxial warp-knitted composites has higher accuracy, which can be used to study the static and dynamic mechanical properties.

PL

Wykonano kompozyt wzmocniony dwuosiową dzianiną osnowową i żywicą epoksydową z zastosowaniem próżniowego przenoszenia żywicy (VARTM). Quasi-statyczne właściwości rozciągania badano doświadczalnie odpowiednio w kierunkach 0° i 90°. Opracowano model skończonych elementów dwuosiowych kompozytów z dzianinami. Dokonano symulacji numerycznej zachowania kompozytów podczas rozciągania, a następnie porównano wyniki teoretyczne z wynikami eksperymentalnymi. Wykazano, że istnieje przybliżona zgodność między wynikami eksperymentalnymi i liczbowymi. Stwierdzono, że błędy maksymalne błędy kształtują się na poziomie 14,52% i 33,29%. Zaprezentowany model elementów skończonych ma wysoką dokładność i można go wykorzystać do badania statycznych i dynamicznych właściwości mechanicznych kompozytów.

10

Decision-theoretic Rough Sets in Incomplete Information System

51%

Yang X. , Lu Z. , Li T.-J.

Fundamenta Informaticae

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2013

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tom Vol. 126, nr 4

353--375

EN

Decision-theoretic rough sets in two kinds of incomplete information systems are discussed in this paper. One is for the classical decision attribute and the other for the fuzzy decision attribute. In complete information system, the universe is partitioned with the equivalence relation. Given a concept, we get a pair of approximations of the concept using rough set theory, and the universe can be partitioned into three regions for making a decision. An incomplete information table can be expressed as a family of complete information tables. The universe is partitioned by the equivalence relation for each complete information table. The probability of each object belonging to the concept can be calculated in a completion from incomplete information system, and then the total probability of the object belonging to the concept can be obtained. Decision rules are derived using total probability instead of conditional probability in decision-theoretic rough sets. Finally, the universe is divided into three regions according to the total probability. A similar approach to fuzzy incomplete information system is examined and the universe is also divided into three regions.

11

Morphological study of the hoof in yak

51%

Yang X. , Ren X. , Yu S. , Cui Y.

Folia Morphologica

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2016

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tom 75

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nr 3

EN

The fore- and hindlimb of yak have been studied by the gross anatomical methods and standard histological techniques. The artery of ungula was also determined by X-ray and acrylonitrile-butadiene-styrene casting. Anatomical features of the forelimb of yak resemble those of hindlimb, including hoof periphery, hoof coronal, hoof wall, hoof sole, and hoof sphere. The forelimb and hindlimb are almost the same in histological structure. The epidermis comprised all 5 strata: stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum and stratum basale. The papillary layers and dermal lamellae contained a variable amount of capillary as well as collagen and elastic fibres. Many venules and arteriovenous anastomosis were distributed among the reticular layer. Subcutaneous tissue was composed of rich adipose and connective tissue in hoof periphery, hoof coronal, and, especially, hoof sphere. Major arteria in forelimb of yak include arteria digitalis palmaris communis III and arteriae digitales palmares propriae III and IV axialis. Those in hindlimb include arteria digitalis plantaris communis III and arteria digitalis plantaris propria III and IV axialis. Our findings highlight the main morphological features of yak and provide a morphological basis useful to researchers using yak hoof. (Folia Morphol 2016; 75, 3: 400–408)

12

The RC Circuit Described by Local Fractional Differential Equations

51%

Zhao X.-H. , Zhang Y. , Zhao D. , Yang X.

Fundamenta Informaticae

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2017

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tom Vol. 151, nr 1/4

419--429

EN

A non-differentiable resistor-capacitor circuit comprised of the capacitor and resistor in the fractal-time domain is first proposed in this article. The solution behavior of the corresponding local fractional ordinary differential equation is presented for the Mittag-Leffler decay defined on Cantor sets. The obtained results reveal the sufficiency of the local fractional calculus in the analysis of the fractal electrical systems.

13

Structures and Spectral Properties of (O-sec.-Butyldithiocarbonatio-S,S') Bis(triphenylphosphine) Copper(I) and Silver(I) Complexes

51%

Han Q. , Yang X. , Lu L. , Wang X.

Polish Journal of Chemistry

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2004

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tom Vol. 78 / nr 1

27-33

EN

New complexes (PPh3)2M(S2COR) [R = sec.-butyl,M= copper (1), silver (2)] were synthesized by the reaction of excessive triphenylphosphine and copper(II) or silver(I) xanthate, and characterized using IR, EA, 1H NMR and TG. Their crystal structures have been determined by X-ray diffraction. The light yellow crystal of the complex (1) is triclinic of space group P1, with parameters a = 10.300(2) A, b = 13.120(3) A, c = 14.570(3)A, _= 89.53(3), _ = 72.81(3), _ = 78.61(3)_, and Z = 2. The yellow crystal of the complex (2) is triclinic of space group P1, with parameters a = 10.330(2) A, b = 13.410(3) A, c = 14.420(3) A, _ = 88.61(3), _ = 73.60(3), _ = 78.93(3)_, and Z = 2. In the two complexes, the central Cu or Ag atom is in a distorted tetrahedral environment and chelated by two phosphorus atoms from the triphenylphosphine groups and two sulfur atoms from the O-alkyldithiocarbonate. IR and 1H NMR results supported the structures. The thermal analytical data indicate that the complex (1) began to decompose at 122.3_ and decomposition was complete at 370.9_, leaving Cu2S, while the complex (2) began to decompose at 133.3_ and decomposed completely at 290.3_ to Ag2S.

14

Moving cast shadow detection using block nonnegative matrix factorization

51%

Yang X. , Liu D. , Zhou D. , Yang R.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2018

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tom Vol. 66, nr 2

229--234

EN

In recent years, moving cast shadow detection has become a critical challenge in improving the accuracy of moving object detection in video surveillance. In this paper, we propose two novel moving cast shadow detection methods based on nonnegative matrix factorization (NMF) and block nonnegative matrix factorization (BNMF). First, the algorithm of moving cast shadow detection using NMF is given and the key points such as the determination of moving shadow areas and the choice of discriminant function are specified. Then BNMF are introduced so that the new training samples and new classes can be added constantly with lower computational complexity. Finally, the improved shadow detection method is detailed described according to BNMF. The effectiveness of proposed methods is evaluated in various scenes. Experimental results demonstrate that the method achieves high detection rate and outperforms several state-of-the-art methods.

15

Effects of iron oxide nanoparticles on the mineral composition and growth of soybean (Glycine max L.) plants

51%

Yang X. , Alidoust D. , Wang C.

Acta Physiologiae Plantarum

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2020

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tom 42

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nr 08

16

Physical purification of diatomite based on laminar-flow centrifugal separation

51%

Yang X. , Sun Z. , Zheng S.

Physicochemical Problems of Mineral Processing

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2014

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tom Vol. 50, iss. 2

705--718

EN

Natural diatomaceous earth or diatomite of good quality becomes rare and a demand for it increases every year. In this paper, we develop a novel method based on laminar-flow centrifugal separation to purify mid- and low-grade diatomite for industrial production purposes. Effects of the drum cone angle, drum speed, feeding concentration, feeding flow rate and feeding time on separation were investigated experimentally. The interdependency of these variables was studied using a response surface experiment. Operating conditions of a laminar-flow centrifugal separator were further optimized. Results showed that the feeding flow rate had a great influence on a silicon dioxide content of diatomaceous in concentrate and tailing. The optimal separation results were achieved as 87.5 wt.%, of SiO2 content of diatomaceous in concentrate and 6.98 wt.% in tailing. The optimal operating conditions included the drum cone angle of 0.0087 rad, the drum speed of 89.62 rad/s, the feeding concentration of 24.66 wt.%, the feeding flow rate of 2.33×10–4 m3/s, and the feeding time of 90 s. A scanning electron microscopy (SEM) clearly indicated that the pore blockage on the surface of diatoms was cleared out. The variation about the breakage rate of diatom shells was lower than 5% through the pilot purification production line. The characterization of original diatomite and derived products after purification were determined by X-ray diffraction (XRD). The results indicated that the impurity content of purified diatomite was improved significantly.

17

Moving cast shadow detection using block nonnegative matrix factorization

51%

Yang X. , Zhou D. , Liu D. , Yang R.

|

18

Role of jasmonate signaling pathway in resistance to dehydration stress in Arabidopsis

51%

Li Y. , Yang X. , Li X.

Acta Physiologiae Plantarum

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2019

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tom 41

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nr 06

EN

The plant hormone jasmonic acid (JA) is critical to plant defense and plant development. Various studies have focused on the regulation of plant biotic stress by JA, but few have assessed its roles in abiotic stress. This study investigated the components of the JA signaling pathway in its response to dehydration stress. coi1-2, 35Spro:JAZ1-ΔJas and myc2-2 mutants disrupted in key regulators of JA signaling were more sensitive to dehydration stress. This suggests that JA signaling plays a key role in resistance to dehydration. Furthermore, we found that the mediation of the dehydration process by JA occurs via the induction of ERD1 expression. And our genetic data showed that ERD1 acts as a positive factor in dehydration stress. The bHLH transcription factor MYC2 could bind to the promoter of its target gene ERD1 and activate its expression to activate the JA-induced response to dehydration stress. Genetic and molecular data indicate that ERD1 functions downstream of the JA-mediated signaling pathway in response to dehydration stress. Our study, thus, reveals the following JA-mediated dehydration signaling pathway: the receptor COI1 perceives the dehydration signal, after which the signal is transmitted to MYC2, which then binds to the promoter of ERD1 and induce its expression. MYC2-induced ERD1 expression then enhances the resistance to dehydration stress. Together, our data strongly suggest a role for the JA signaling pathway in response to dehydration stress.

19

The Development of the Flat-Knitted Shaped Uppers based on Ergonomics

51%

Lu Z. , Jiang G. , Cong H. , Yang X.

Autex Research Journal

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2016

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tom Vol. 16, no. 2

67--74

EN

To achieve the efficiency and specification of the flat-knitted uppers design, the basic patterns of uppers are made from shoe lasts based on the research on the characteristics of human’s feet and wearability requirements on uppers. The knitting technology for half-shaped and fully shaped uppers was formed after the shear deformation of basic pattern and combination with flat knitting technology. As regards to the functional requirements on key parts of uppers, the structures of flat-knitted shaped uppers were intensively analysed and studied, dividing them into two categories (functional structure and decorative structure), discussing the knitting methods and advantages of different structure, and finally experimentally proving that the planar pattern of flat knitted uppers can apply to the design of flat-knitted uppers and achieve the combination of functionality and artistry of sneakers after combining with structural changes, with a great significance on the achievement of the efficient production of uppers and the enhancement of its commercial value.

20

Two-objective optimization design for the transcutaneous energy transmission system

51%

Bai L. , Liangyu B. , Hounjun T. , Yang X.

Przegląd Elektrotechniczny

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2011

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tom R. 87, nr 6

180-185

EN

The Transcutaneous energy transmission (TET) systems suffer two major drawbacks, due to the weak mutual coupling and large leakage inductance: low efficiency and low power transfer capability. This paper proposes an optimization method which considers both efficiency and power transfer capability to meet different practical application. We have used MATLAB/SIMULINK to verify the analytical results. A comparison of the results validates our optimization method, and shows enhanced performance.

PL

Bezprzewodowy system transmisji energii TET stosowany przy implantach jest obarczony niedogodnościami – słabym sprzężeniem obwodów, dużą indukcyjnością rozproszenia i małą efektywnością. W artykule zaproponowano optymalizację tego systemu.