Wyniki wyszukiwania - Biblioteka Nauki

1

On Quasi-discrete Fuzzy Closure Spaces

100%

Liu G.

Fundamenta Informaticae

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2015

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tom Vol. 142, nr 1-4

105--115

EN

This paper studies quasi-discrete closure spaces and fuzzy closure spaces. We show that any topological closure cT induced by a closure c is the smallest extension from a closure space to a topological closure space in both crisp and fuzzy environment, in addition, a characterization of the continuous mappings in quasi-discrete closure spaces is obtained. We propose the concept of quasi-discrete fuzzy closure spaces in the context of fuzzy sets and establish a one to one correspondence between quasi-discrete fuzzy closure spaces and reflexive fuzzy relations. We also discuss the relationship between topological closure cT and closure c in quasi-discrete fuzzy closure spaces and show that the process from closure c to topological closure cT can be realized via the process from a reflexive fuzzy relation to its transitive closure.

2

Level Mapping Induced Loop Formulas for Weight Constraint and Aggregate Logic Programs

63%

Liu G. , You J.-H.

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tom Vol. 101, nr 3

237-255

EN

Level mapping and loop formulas are two different means to justify and characterize answer sets for normal logic programs. Both of them specify conditions under which a supported model is an answer set. Though serving a similar purpose, in the past the two have been studied largely in isolation with each other. In this paper, we study level mapping and loop formulas for weight constraint and aggregate (logic) programs. We show that, for these classes of programs, loop formulas can be devised from level mapping characterizations. First, we formulate a level mapping characterization of stable models and show that it leads to a new formulation of loop formulas for arbitrary weight constraint programs, without using any new atoms. This extends a previous result on loop formulas for weight constraint programs, where weight constraints contain only positive literals. Second, since aggregate programs are closely related to weight constraint programs, we further use level mapping to characterize the underlying answer set semantics based on which we formulate loop formulas for aggregate programs. The main result is that for aggregate programs not involving the inequality comparison operator, the dependency graphs can be built in polynomial time. This compares to the previously known exponential time method.

3

Study on application of Fisher information for power system fault detection

63%

Cai S. , Liu G.

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2018

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tom Vol. 98, nr 3

274--280

EN

The ability to accurately detect power system faults is of vital importance for the purpose of isolating malfunctioning equipment and resuming normal operation as soon as possible after a fault occurs. People have used a variety of electric parameters as metrics to identify faults for a long time. The method proposed by this paper departs from the traditional approach by introducing Fisher information (FI) as a measure of the stability of electric signals and as a criterion for making fault decisions. In this way, a non-dimensional positive parameter is used as a single criterion to deliver fault detection for power distribution networks. Firstly, we simplified the formula of FI and then adopted a practical method for calculating values of FI. We demonstrated the application of FI to measure the stability of electric signals. Finally, we combined FI with wavelet analysis to propose a novel technique for phase selection of a power distribution network with a grounding short-circuit fault, namely the wavelet-based Fisher information (WFI). Simulation studies were then carried out to show the feasibility of the proposed method.

4

Level Mapping Induced Loop Formulas forWeight Constraint and Aggregate Logic Programs

63%

Liu G. , You J.-H.

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2011

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tom Vol. 106, nr 1

25-43

EN

Level mapping and loop formulas are two different means to justify and characterize answer sets for normal logic programs. Both of them specify conditions under which a supported model is an answer set. Though serving a similar purpose, in the past the two have been studied largely in isolation with each other. In this paper, we study level mapping and loop formulas for weight constraint and aggregate (logic) programs. We show that, for these classes of programs, loop formulas can be devised from level mapping characterizations. First, we formulate a level mapping characterization of stable models and show that it leads to a new formulation of loop formulas for arbitrary weight constraint programs, without using any new atoms. This extends a previous result on loop formulas for weight constraint programs, where weight constraints contain only positive literals. Second, since aggregate programs are closely related to weight constraint programs, we further use level mapping to characterize the underlying answer set semantics based on which we formulate loop formulas for aggregate programs. The main result is that for aggregate programs not involving the inequality comparison operator, the dependency graphs can be built in polynomial time. This compares to the previously known exponential time method.

5

Research on time-varying characteristics of testability index based on renewal process

51%

Zhao Z. , Qiu J. , Liu G. , Zhang Y.

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tom Vol. 18, no. 3

457--468

EN

Testability indices are used in the phases of testability design and testability demonstration. This paper focuses on fault detection rate (FDR), which is the most widely used testability index. Leading hypothesis suggests that the value of FDR of a system is usually a certain value. However, few attempts have been made to research the statistical characteristics of FDR. Considering the fault occurrence process and test uncertainty, FDR is time varying and a special statistical process. Under the assumption of perfect repairs, we build a fault occurrence model based on the renewal process theory. Supposing that test uncertainty is mainly induced by test fault, the renewal process is employed to depict the occurrence process of test faults. Simultaneously, we depict the process of test state change and then construct the fault detection logic based on the digraph model. Combining the fault occurrence model and the fault detection logic, we focus on the expectation of FDR, which is one of the key statistical characteristics. By comparison, we introduce the calculation method of expectation of FDR in two cases, including without considering test uncertainty and considering test uncertainty. To validate the conclusions presented in this paper, we carry on a simulation case using an integrated controller. Based on the theoretic and simulating methods, the expectation of FDR tends to be a constant with the increase of time under the assumptions made in this paper. The statistical characteristic of FDR presented in this paper would be the basic theoretical guide to testability engineering.

PL

Wskaźniki testowalności wykorzystuje się w fazach projektowania oraz potwierdzania testowalności. Przedstawiony artykuł poświęcony jest wskaźnikowi wykrywalności błędów (fault detection rate, FDR), który jest najczęściej stosowanym wskaźnikiem testowalności. Wiodąca hipoteza sugeruje, że wartość FDR dla danego systemu jest zwykle wartością pewną. Istnieje jednak niewiele badań na temat statystycznych własności FDR. Biorąc pod uwagę proces występowania błędów oraz niepewność pomiarów, współczynnik FDR można opisać jako zmienny w czasie specjalny proces statystyczny. Przy założeniu naprawy doskonałej, zbudowaliśmy model występowania błędów w oparciu o teorię procesu odnowy. Przyjmując, że niepewność testową wywołują głównie błędy testowe, wykorzystaliśmy proces odnowy do zobrazowania procesu występowania błędów testowych. Jednocześnie przedstawiliśmy proces zmiany stanu testu, a następnie zbudowaliśmy logikę wykrywania błędów w oparciu o model grafu skierowanego. Łącząc model występowania błędów z logiką wykrywania błędów, opracowaliśmy metodę obliczania wartości oczekiwanej FDR, która jest jedną z najważniejszych własności statystycznych tego wskaźnika. Dla porównania, metodę obliczania wartości oczekiwanej FDR zastosowaliśmy w dwóch przypadkach, z uwzględnieniem i bez uwzględnienia niepewności testowej. Aby zweryfikować wnioski przedstawione w niniejszej pracy, przeprowadziliśmy symulację z wykorzystaniem zintegrowanego kontrolera. Obliczenia teoretyczne i symulacja pokazują, że wartość oczekiwana FDR wraz z upływem czasu staje się wartością stałą w warunkach założonych w niniejszej pracy. Przedstawiona w artykule charakterystyka statystyczna FDR stanowi jedną z podstaw teoretycznych inżynierii testowej.

6

Description of a new brackish water ciliate, Uronychia xinjiangensis n. sp. (Ciliophora, Euplotida) based on morphology, morphogenesis and molecular phylogeny

51%

Shi X. , Liu G. , Wang C. , Hu X.

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nr 4

7

Effects of Bothriochloa ischaemum characteristics induced by nitrogen addition on the process of slope runoff and sediment yield

51%

Li P. , Li B. , Wang J. , Liu G.

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tom 30

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nr 1

8

Study on the design of container highway and railway automatic transfer vehicle in ocean port

51%

Dong L. , Liu G. , Ye X. , Wang W.

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2018

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tom S 3

5--12

EN

To realize “seamless” connection of ocean port container multimodal transport, efficiently carry out “door-to-door” transport of ocean port containers and overcome the shortcomings of existing highway and railway vehicles, this study takes the standard for heavy-duty container vehicles in TB1335-1996 Railway Vehicle Strength Design and Test Identification Code as the design basis and designs a new ocean port container transport vehicle in combination with automatic guidance technology. This study innovatively designs the automatic lifting system of the bogie and the docking part of the vehicle, introduces the automatic guidance technology and the remote-control technology to optimize the car body structure, and uses the SAP software to carry out the finite element analysis of the car body load capacity and Flexsim software to carry out the simulation analysis on the operation of vehicles. The designed transfer vehicle can improve the transfer efficiency of ocean port containers, reduce the transit time of field and station equipment and container transport links, and improve the level of multimodal transport and comprehensive economic benefits.

9

An experimental investigation into the radial compressive properties of the biodegradable braided regeneration conduits for peripheral nerve repair

51%

Liu G. , Hu H. , Zhang P. , Wang W.

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2005

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tom Vol. 5, no. 2

106--112

EN

Different regeneration conduits braided from biodegradable material poly (glycolide-co-L-lactide) (PGLA) for peripheral nerve repair and their radial compressive properties are presented. The influences of the braided structure and braiding angle are discussed. The results have shown that the nerve conduit braided with the triaxial structure at 60 degrees of the braiding angle has a greater ability to resist radial compression.

10

Study on the design of container highway and railway automatic transfer vehicle in ocean port

51%

Dong L. , Liu G. , Ye X. , Wang W.

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nr Special Issue S3

EN

To realize “seamless” connection of ocean port container multimodal transport, efficiently carry out “door-to-door” transport of ocean port containers and overcome the shortcomings of existing highway and railway vehicles, this study takes the standard for heavy-duty container vehicles in TB1335-1996 Railway Vehicle Strength Design and Test Identification Code as the design basis and designs a new ocean port container transport vehicle in combination with automatic guidance technology. This study innovatively designs the automatic lifting system of the bogie and the docking part of the vehicle, introduces the automatic guidance technology and the remote-control technology to optimize the car body structure, and uses the SAP software to carry out the finite element analysis of the car body load capacity and Flexsim software to carry out the simulation analysis on the operation of vehicles. The designed transfer vehicle can improve the transfer efficiency of ocean port containers, reduce the transit time of field and station equipment and container transport links, and improve the level of multimodal transport and comprehensive economic benefits

11

Detection of Antarctic oscillation signals in Earth’s oblateness variations

51%

Duan P. , Liu G. , Tu Y. , Huang C.

Acta Geophysica

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2017

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tom Vol. 65, no. 4

635--644

EN

Variations of Earth’s oblateness (J2) reflect a large scale mass redistribution within the Earth system. The climate effect causing J2 interannual variations is still not clear, though previous studies indicated it may be related to El Niño–Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). However, we have a new discovery of the significant Antarctic Oscillation (AAO) signals in J2 interannual variations, especially on 4–6 year scales based on cross wavelet and wavelet coherence analysis with 95% confidence test during 1979–2012. The results additionally indicate that the close phase relationship between J2 and AAO (AAO leading J2 variations by 3 ± 2 months in phase) is far superior to that between J2 and ENSO/PDO on 4–6 year scales. In this work, we discuss, for the first time, a possible geophysical mechanism of AAO effecting J2 variations. The investigations are based on the definition of AAO and its spatial-temporal behavior influencing the large-scale mass movement. Finally, an approximate quantitative estimate of the AAO imprint on J2 with an emphasis on the atmospheric contribution is made.

12

Effects of disperser abundance, seed type, and interspecific seed availability on dispersal distance

51%

Liu C. , Liu G. , Shen Z. , Yi X.

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nr 3

EN

Seed dispersal distance is influenced by a variety of seed properties and functional responses of dispersers. However, to our knowledge, how and why seed dispersal distances are determined remains poorly understood. In the present study, seeds of sympatric tree species, Pinus koraiensis, Corylus mandshurica, Corylus heterophylla, and Quercus mongolica were released to investigate the effects of rodent abundance, seed type, and seed availability on seed dispersal. Our results showed that seeds of P. koraiensis were dispersed further than those of C. heterophylla and C. mandshurica regardless of the ambient rodent and seed abundances, reflecting a consistent effect of seed type on seed dispersal distances. Seed dispersal distance was greatly facilitated by lower per-capita seed abundance (the ratio of seeds to rodents); however, seed caching and cache survival were benefited from higher per-capita seed abundance. Although seed dispersal and seed caching of a particular tree species can be enhanced by its own seed availability, no consistent influence was detected at interspecific levels, reflecting different interspecific effects of seed availability on seed dispersal of sympatric seed species. Our results provide evidences that the effect of seed availability on seed dispersal should be evaluated in terms of per-capita seed abundance and interspecific effects, rather than the independent influence of seed or disperser abundances.

13

Seed vigor, photosynthesis and early growth of saplings of different triploid Betula families

51%

Mu H. , Jiang J. , Li H. , Liu G.

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tom 68

EN

Breeding scientists have given extensive attention to triploids in trees because of their importance to forestry. Consequently, creating and breeding triploids of good quality has become one of purposes of tree breeding. We chose two autotetraploids (Betula platyphylla, named Q10 and Q65) as female parents and eight hybrid diploids (B. platyphylla × B. pendula, named F1 – F8) as male parents to obtain progenies through controllable pollination, resulting in triploid progenies. Germination rate and germination energy of triploid seeds of Q65 were significantly higher (P < 0.01) than in triploid seed s of Q10. Triploid families with Q65 as female parent had a large quantity of saplings, whereas triploid families with Q10 as female parent had a small quantity of saplings. Triploid families with Q65 as female parent were generally superior in base diameter and height to base diameter ratio when compared to a diploid family. Q65×F3 was preliminarily recognized as the superior family. These results demonstrate that the female parent has a major influence on triploid progenies, although the male parent also has a small influence. The results provided a reference to build seed orchards of triploid birch trees, choose tetraploids as female parents and forecast triploid families of good quality.

14

Robust L2 consensus of high-order swarm systems with time-varying delays

51%

Xi J. , Yao Z. , Liu G. , Zhong Y.

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2014

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tom Vol. 43, no. 1

59--77

EN

Consensus problems for high-order continuous-time swarm systems in directed networks with time delays, uncertainties and external disturbances are investigated. Firstly, the state space of a swarm system is decomposed into a consensus subspace (CS) and a complement consensus space (CCS). A necessary and sufficient condition for the system with time delays and uncertainties to achieve consensus is presented based on the state projection on CCS, and an explicit expression of the consensus function is shown on the basis of the state projection on CS. Then, a sufficient condition for the system to achieve consensus with a desired L2 performance is given. Finally, numerical simulations are shown to demonstrate theoretical results.

15

Study on the optimization and performance of TDMA allocation algorithm in ships’ ad hoc networks

51%

Han X. , Li Y. , Liu G.

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nr Special Issue S2

EN

This paper analyzes the requirements of the information transmission network of ship integrated condition monitoring system, and proposes a design scheme of ship condition monitoring system based on wireless ad hoc network. The wireless ad hoc network protocol was designed, its networking process was analyzed in detail, and the network transmission performance of the monitoring system was tested. The results proved the feasibility of the system. The above solution can be used for the transmission of ship state information that satisfies the requirements of wireless transmission, and has important theoretical and practical significance. The slot allocation algorithm has been receiving extensive attention as an important part of the TDMA system research. This paper analyzes the summarization and summarization of TDMA time slot assignment algorithms from several aspects such as slot synchronization, existing slot allocation algorithm, and slot assignment model, laying an important foundation for researchers to do further research. In the TDMA system, time is divided into non-overlapping time frames, and the time frames are divided into non-overlapping time slots. Each node in the network performs corresponding operations in each time slot

16

Production of Carbon Fibre Bulked Yarns by the Airflow Dispersion Method

51%

Zhao X. , Liu Y. , Liu G.

Fibres & Textiles in Eastern Europe

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2017

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tom Vol. 25, no. 6 (126)

34--40

EN

Using carbon fibre tows as raw materials, carbon fibre bulk yarns were producedby the airflow dispersion method for the first time. The breaking strength, strength irregularity, yarn irregularity and hairiness index of the carbon fibre bulk yarn were used as evaluation indices, and preparation technology for carbon fibre bulk yarn was optimized using the orthogonal experimental method. Subsequently the disordered structure of homemade carbon fibre bulk yarn, the ability to fix the resin, and the surface contact angle were investigated. Finally infrared spectral analysis of the carbon fibre bulk yarn was carried out. Results show that the best preparation technology for carbon fibre bulk yarn is as follows: nozzle air pressure 0.45 MPa, spinning speed 150 m/min, and nozzle diameter 2.2 mm. The degree of disorder of fibres of T700 carbon fibre bulk yarn fibre is 18.70%~25.60%; as the degree of disorder of carbon fibre bulk yarn increases, the ability to fix the resin is enhanced. The process of carbon fibre tows producing bulk yarns is a physical one.

PL

W pracy wytworzono przędze puszyste z włókien węglowych metodą dyspersji przepływu powietrza, następnie zbadano ich wytrzymałość na rozerwanie, nierównomierność oraz włochatość. Przeprowadzono także spektralną analizę wiązki włókien węglowych w podczerwieni. Na podstawie otrzymanych wyników określono optymalne parametry wytwarzania przędz puszystych z włókien węglowych, tj.: ciśnienie powietrza w dyszy 0,45 MPa, prędkość wirowania 150 m/min i średnica dyszy 2,2 mm. Stopień nieuporządkowania włókien węglowych T700 wynosi 18,70 ~ 25,60%. Stwierdzono, że wraz ze wzrostem stopnia nieuporządkowania zwiększa się zdolność wiązania żywicy.

17

Research progress in allele-specific expression and its regulatory mechanisms

51%

Gaur U. , Li K. , Mei S. , Liu G.

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2013

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tom 54

|

nr 3

18

Spatial distribution and influence analysis of soil heavy metals in a hilly region of sichuan basin

51%

Liu H. , Liu G. , Zhou Y. , He C.

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tom 26

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nr 2

EN

The hilly region of the Sichuan basin has unique natural topography, geomorphology, geology, and hydrology, with intensive human activities in the area. Therefore, it is of great significance to carry out research on heavy metal characteristics. In this study, taking five villages of Zigong city as a sample, the content of eight kinds of heavy metals in soil was determined (Cu, Cd, As, Pb, Cr, Zc, Ni, and Hg) based on ordinary Kriging. The results showed that Cd, Pb, Ni, and Zn content in the research area was higher than the background value and had a good concentration with all of the heavy metal contents lying within the national standards. Through soil parent material, soil environment, atmospheric environment, and water environment analysis of heavy metals, it was found that higher levels of heavy metals in the research area were mainly affected by agricultural and industrial activities (atmospheric dustfall). This was generally where there were intense areas of human activity – especially in and around transport routes and construction areas. It was also found that the soybean crop exhibited a strong Cd accumulation ability. This soybean planting should be reduced to control the distribution of Cd. Zn and Cu had a positive enrichment effect on rice, soybeans, and other crops, and had little enrichment effect on grapefruit. This study showed the effect human activities have on the quality of soil quality on the crop. This research has great significance for the ecologically sustainable development of society.

19

Complexation of poly(ethylene glycol) with poly(ethyl methacrylate-co-N-vinyl-2-pyrrolidone) gel based on hydrogen bonds

51%

Liu G. , Xie D. , Guan C.

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tom Vol. 15, nr 3

85-90

EN

The complexes of poly(ethyl methacrylate-co-N-vinyl-2-pyrrolidone) (P(EMA-co-VP)) gel with poly- (ethylene glycol) (PEG) stabilized by the hydrogen bonds were prepared. It was found that both the concentration and the molecular weight of PEG have a strong effect on the P(EMA-co-VP) gel. When PEG was introduced into the P(EMA-co-VP) gel, the glass transition temperatures (Tg) of the complexes decreases with the decreasing of PEG molecular weight. In such a system, the maximum molecular weight of PEG required for the complex formation is no more than 2000, and P(EMA-co-VP)/PEG complexes are a homogeneous amorphous phase, which was studied by FTIR, XRD, TEM, and DSC.

20

Redescription of morphology and morphogenesis of the freshwater ciliate, Pseudokeronopsis similis [Stokes, 1886] Borror et Wicklow, 1983 [Ciliophora: Urostylida]

51%

Shi X. , Hu X. , Warren A. , Liu G.

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nr 1