Wyniki wyszukiwania - BazTech

1

Stability of air nucleus in liquid water and cavitation inception on marine engineering

Fu Q., Chen M., Wang X., Zhu R., Zhang G.

Polish Maritime Research

|

2018

|

S 3

111--119

EN

The micro air nucleus widely distributed in the ocean is a necessary condition for the cavitation of hydraulic machinery in seawater. In order to study the stability of air nucleus in seawater and cavitation inception, the computational domain of water molecules with air nucleus was studied using the method of molecular dynamics simulation, and the transient characteristics of air nucleus in liquid water were obtained. The key factors influencing nuclei stability were analyzed. The results showed that air nucleus with a certain mass could maintain the dynamic equilibrium in liquid water. The internal density of air nuclei had a critical value that allowed the nuclei to stably exist in water. The air nuclei mass was the decisive factor in its equilibrium volume in water, and the two were positively correlated. The internal density of air nuclei was negatively correlated with the nuclei radius when the nuclei was stable in water. Liquid surface tension was an important factor affecting the stability of the air nuclei. The larger the initial radius of nuclei, the smaller the water pressure, and the more likely the cavitation occurs.

2

A comprehensive and practical reliability allocation method considering failure effects and reliability costs

Yu H., Zhang G., Ran Y., Li M., Wang Y.

Eksploatacja i Niezawodność

|

2018

|

Vol. 20, no. 2

244--251

EN

In view of the drawbacks in existing allocation methods which are incomplete considerations and poor practicality, a comprehensive fuzzy allocation method considering failure effects and reliability costs is proposed. Fuzzy linguistics and triangular fuzzy numbers are used to evaluate the uncertainty and subjective factors in allocation process. The traditional risk priority numbers (RPNs) are modified to overcome the shortages which are the same factor weights and equal difference of failure effects in original methods. State of the arts, components intricacy and working conditions are used to construct the reliability costs model, which solves the difficulties of costs statistics and avoids the sophisticated calculations which exist in current allocation methods. The relationship between reliability costs and potential risk of subsystem is studied and the value range of it is given in this paper. A case example is given to illustrative the scientificity and practicability of proposed allocation method.

PL

Ze względu na niedostatki istniejących metod alokacji, które nie dają pełnego obrazu problematyki i mają słabe zastosowanie w praktyce, w artykule zaproponowano kompleksową metodę alokacji opartą na logice rozmytej, uwzględniającą skutki uszkodzeń i koszty niezawodności. W pracy wykorzystano lingwistykę rozmytą i trójkątne liczby rozmyte do oceny niepewności i czynników subiektywnych w procesie alokacji. Zmodyfikowano tradycyjny wskaźnik liczby priorytetowej ryzyka (RPN), co pozwoliło na poprawę mankamentów charakteryzujących oryginalną metodę, t.j. takie same współczynniki wagowe i równoważność skutków uszkodzeń o różnym stopniu ciężkości. Na podstawie wiedzy o stanie techniki, złożoności komponentów i warunkach pracy, skonstruowano model kosztów niezawodności, który rozwiązuje trudności dotyczące sporządzania statystyki kosztów i pozwala uniknąć skomplikowanych obliczeń stosowanych w obecnych metodach alokacji. Zbadano związek między kosztami niezawodności a potencjalnym ryzykiem podsystemu, oraz podano jego zakres wartości. Prezentowane studium przypadku demonstruje możliwe zastosowania i efektywność proponowanej metody.

3

Influence of Polytetrafluorethylene on the Mechanical and Safety Properties of a Composite Modified Double Base Propellant

Sun S., Zhang T., Zhao B., Zhang G., Li X., Luo Y.

Central European Journal of Energetic Materials

|

2018

|

Vol. 15, no. 3

468--484

EN

A novel Composite Modified Double Base (CMDB) propellant, formed by mechanically mixing aluminium/polytetrafluorethylene (Al/PTFE) powders, was prepared through a rolling process. A variety of tests, such as tensile properties, particle size analysis etc., were carried out to study the influence of PTFE on the CMDB propellant properties. The PTFE deformed from particles to fibres under a uniform shear force, forming a fibre network which greatly improved the propellant’s mechanical properties. Compared to that of the CMDB propellant without PTFE, the elongation of the propellant containing 6% PTFE was increased by 26 times, and moreover, the impact strength was enhanced by 326% at −40 °C. Significantly, the propellant friction and impact sensitivities were reduced by 75.8% and 35.6%, respectively. In addition, the presence of PTFE in the propellant resulted in fluorination of the Al. The gaseous combustion product AlF3 reduced the propellant combustion agglomeration. Consequently, PTFE significantly promoted the propellant’s mechanical performance, decreased the shock (friction, impact) sensitivity and reduced combustion agglomeration.

4

Effect of ammonium sulfate on the sulfidation flotation of malachite

Liu C., Feng Q., Zhang G.

Archives of Mining Sciences

|

2018

|

Vol. 63, no. 1

139--148

EN

The effect of ammonium sulfate on the sulfidation flotation of malachite was investigated by micro-flotation tests, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) measurements. Micro-flotation results show that the sodium sulfide concentration and strring time are difficult to control on the sulfidation flotation of malachite. However, when ammonium sulfate was used, the detrimental effect of mixing time and high dosage of sodium sulfide on the sulfidization flotation of malachite can be efficiently eliminated. SEM results showed that sulfidized film on malachite in the presence of ammonium sulfate, and EDS analysis results showed that more S element absorbed and distributed equality on the malachite surface, which was agreed well with the macro-flotation results.

PL

Badano wpływ siarczanu amonu na przebieg procesu siarczkowania w trakcie flotacji malachitu przy wykorzystaniu badania mikroskopowego, mikroskopii elektronowej skanningowej (SEM) oraz pomiarów spektrometrycznych rozpraszania energii EDS. Testy mikroskopowe wykazały, że stężenie siarczku sodu i długość czasu mieszania są parametrami, które niezwykle trudno kontrolować w trakcie procesu siarczkowania towarzyszącemu flotacji malachitu. Z kolei przy zastosowaniu siarczanu amonu, udaje się skutecznie wyeliminować niekorzystne efekty związane z czasem mieszania oraz wysokimi stężeniami siarczku sodu w trakcie flotacji malachitu poprzez siarczkowanie. Wyniki mikroskopii skaningowej wskazują, że przy zastosowaniu siarczanu amonu powstaje cienki film siarczkowy na malachicie zaś pomiary spektrometryczne wykazały większe ilości zaabsorbowanej i bardziej równomiernie rozłożonej siarki pierwiastkowej S na powierzchni malachitu, co pozostaje w pełnej zgodności z wynikami uzyskanymi z badania procesu flotacji w skali makro.

5

Phase Transition and Plasticity Enhancement of Ti-Cu-Based Bulk Metallic Glasses

Wang L., Wang X., Zhang G., Sun X.

Archives of Metallurgy and Materials

|

2018

|

Vol. 63, iss. 1

387--391

EN

In this paper, we report the complex crystallization kinetics of phase transition happening in Ti-Cu-based bulk metallic glasses (BMGs), which play significant roles in the glass formation with respect to their low reduced glass transition temperatures, Trg. The first exothermic event just occurs when annealing the BMG samples in the supercooled liquid region, leading to the Avrami exponent deviating from conventional modes affected by the residual amorphous phase. For Ti43Cu43Ni7Zr7 BMG, the plasticity can be improved by pre-annealing at a sub-Tg temperature of 623K (≈50K below Tg) for 0.5 hour, however, deteriorated by 1 hour annealing, which could be related to the change in stability of this BMG against crystallization with different pre-annealing times.

6

Analytical study of the reflection and transmission coefficient of the submarine interface

Zhang G., Hao C., Yao C.

Acta Geophysica

|

2018

|

Vol. 66, no. 4

449--460

EN

The analytical study of the reflection and transmission coefficient of the seafloor interface is essential for the characterization of the ocean bottom in marine seismic exploration. Based on the boundary conditions of the seafloor interface, the analytical expression of the reflection and transmission coefficient at the submarine interface is derived in this study by using the steady-state wave solution of the elastic wave in a homogeneous, isotropic medium. With this analytical expression, the characteristics of the reflection and transmission coefficient at the submarine interface are analysed and discussed using critical angles. The results show that the change in the reflection and transmission coefficient with the incidence angle presents a ‘‘segmented’’ characteristic, in which the critical angle is the dividing point. The amplitude value and phase angle of the coefficient at the submarine interface change dramatically at the critical angle, which is related to the P- and S-wave velocities in the seabed layer. Compared with the stiff seabed, the soft seabed has a larger P-wave critical angle and an absence of the converted S-wave critical angle, owing to the low P- and S-wave velocities in the solid seabed layer. By analysing and discussing the special changes that occur in the coefficient values at the critical angle, the reflection and transmission characteristics of the different incident angles are obtained. Synthetic models of both stiff and soft seafloors are provided in this study to verify the analytical results. Finally, we compared our synthetic results with real data from the Gulf of Mexico, which enabled the validation of our conclusions.

7

A validated RP-HPLC method for quantitative determination of related impurities of cholic acid bulk drugs

Sheng Z., Ye R., Ge S., Wang C., Xu X., Zhang G., Luo P.

Acta Chromatographica

|

2018

|

Vol. 30, no. 2

114--118

EN

An efficient and convenient reversed-phase high-performance liquid chromatography method has been developed and validated for the quantitative determination of cholic acid bulk drugs and their related impurities. Chromatographic separation was performed on a YMC-Pack ODS-AQ column (250 mm × 4.6 mm, S-5 μm, 12 nm), and the mobile phase consisted of acetonitrile, methanol, and diluted formic acid solution (pH 2.5) at a flow rate of 1.0 mL/min. The analytes were monitored using a refractive index detector at 30 °C, and the column temperature was 30 °C. Under the above chromatographic conditions, the method has good specificity and specified impurities can be effectively separated. The proposed method is found to have linearity in the 2.0–80.0 μg/mL concentration range with correlation coefficients of not less than 0.9999. The compounds analyzed in the solutions are stable for at least 7 days, and spike recoveries for all specified impurities range from 91.3% to 109.3% with relative standard deviations (RSDs) not more than 7.3%. The limit of detection and the limit of quantification for the analytes are 0.060 μg/mL and 2.0 μg/mL, respectively. The proposed method can be applied in the quality control assay of cholic acid bulk drugs, with the advantages of simplicity, accuracy, robustness, good selectivity, and high sensitivity.

8

Półciągła beztlenowa kofermentacja obornika świńskiego i krowiego w produkcji biogazu

Li J., Wei L., Duan Q., Zhang G., Li S., Kong C.

Przemysł Chemiczny

|

2017

|

T. 96, nr 10

2145--2151

PL

Określono parametry półciągłej beztlenowej kofermentacji obornika świńskiego (OŚ) i obornika krowiego (OK) zmieszanych w 5 proporcjach masowych (OŚ/OK). W procesie wyróżniono 3 etapy: rozruch, produkcję gazu oraz zatrzymanie procesu. Dużą zawartość metanu w biogazie (ok. 64%) i małą zawartość części lotnych (ok. 34%) uzyskano dla mieszaniny o proporcji OŚ/OK 5:5. Przy proporcjach OŚ/OK 7:3 i 9:1 uzyskano dużą produktywność biogazu, odpowiednio 0,56 L/(L·d) oraz 0,63 L/(L·d). Mieszaniny OŚ/OK 1:9 i 3:7, z produktywnością gazu ok. 0,42 L/(L·d), okazały się najmniej korzystne w całym procesie. Analiza elementarna wykazała początkową zawartość węgla (27-30%), fosforu (0,7-0,8%) i żelaza (0,29-0,35%) w surowcu. Stosunek OŚ/OK 7:3 zwiększył fermentację biogazu, a akumulacja azotu i fosforu spowodowała zahamowanie fermentacji.

EN

Pig and cattle manures were mixed in mass ratio 1:9 to 9:1 and cofermented to biogas under lab. conditions (bioreactor volume 800 mL) for 47 days after addition of municipal sewage as inoculum. A high MeH content (about 64%) in biogas was reached for the ratio of manures 5:5 while high biogas productivity was obtained at the ratios 7:3 and 9:1.

9

Multiple Frequency Ultrasounds Assisted Oil Sands Separation Technology

Liao K., Ge J., Zhang G., Fu L.

Archives of Acoustics

|

2017

|

Vol. 42, No. 4

767--773

EN

Ultrasound has a wide range of applications in oil sands separation industry due to its green and nopolluting characteristics. The combined ultrasounds technology has been widely used in many industries by virtue of the synergistic effect of cavitation effect; meanwhile, dual-frequency ultrasounds have been reported being used in lotion oil sands technology. Based on this idea, this study focuses on the application of multiple frequency ultrasounds in oil sands separation, and a comparative study has been conducted between the combined ultrasounds systems with the difference in the number of the ultrasound. The results show that the oil production rate of the samples treated by the lotion of sodium dodecyl benzene sulfonate (SDBS) and assisted by multiple frequency ultrasounds (96%) is significantly higher than that of the single frequency ultrasound (76%); the bigger the number of the ultrasound participating in the combination is, the higher the oil production rate of the oil sands is; the lower the frequency of the ultrasounds employed in the combined system is, the higher the oil production rate is. The optimum treating conditions for tri-frequency ultrasounds assisted technology are as follow: the treating time is 10-15 min, the treating temperature is 20-30°C, the concentration of surfactant in the lotion is 1.5 g/l, and the mass ratio of the lotion to oil sands is 1.8. In short, the use of multiple frequency ultrasounds can improve the oil production rate of oil sands, reduce the energy consumption during the separation process, and reduce the environmental contamination; therefore, multiple frequency ultrasounds assisted oil sands separation technology is a promising technology for oil sands resources exploitation with high efficiency.

10

Sewage sludge as barrier material for heavy metals in waste landfill

Zhang H., Yang B., Zhang G., Zhang X.

Archives of Environmental Protection

|

2016

|

Vol. 42, no. 2

52--58

EN

Heavy metal pollutants in the leachate of waste landfill are a potential threat to the environment. In this study, the feasibility of using municipal sewage sludge as barrier material for the containment of heavy metal pollutants from solid waste landfills was evaluated by compaction test and hydraulic conductivity test concerning compaction property, impermeability and heavy metal retardation. Results of the compaction test showed that the maximum dry density of 0.79 g·cm−3 was achieved at the optimum water content of about 60%. The hydraulic conductivities of compacted sewage sludge permeated with synthetic heavy metal solutions were in the range of 1.3×10−8 – 6.2×10−9 cm·s−1, less than 1.0 ×10−−7cm·s−1 recommended by regulations for barrier materials. Chemical analyses on the effluent from the hydraulic conductivity tests indicated that the two target heavy metals, Zn and Cd in the permeants were all retarded by compacted sewage sludge, which might be attributed to the precipitation and adsorption of heavy metal ions. The results of this study suggest that specially prepared material from sewage sludge could be used as a barrier for waste landfills for its low permeability and strong retardation to heavy metal pollutants.

11

Optimal control strategy for marine SSP podded propulsion motor based on strong tracking-EPF

Yao W., Liu Y., Sun H., Zhang G., Zhang J., Zhou M., Sun M., Jiang D.

Polish Maritime Research

|

2015

|

S 1

4--9

EN

Aiming at the non-linearity of state equation and observation equation of SSP (Siemen Schottel Propulsor) propulsion motor, an improved particle filter algorithm based on strong tracking extent Kalman filter (ST-EKF) was presented, and it was imported into the marine SSP propulsion motor control system. The strong tracking filter was used to update particles in the new algorithm and produce importance densities. As a result, the problems of particle degeneracy and sample impoverishment were ameliorated, the propulsion motor states and the rotor resistance were estimated simultaneously using strong track filter (STF), and the tracking ability of marine SSP propulsion motor control system was improved. Simulation result shown that the improved EPF algorithm was not only improving the prediction accuracy of the motor states and the rotor resistance, but also it can satisfy the requirement of navigation in harbor. It had the better accuracy than EPF algorithm.

12

Simulation of the thermo-optic coupling effect in mid-infrared second harmonic generation of ZnGeP2 crystal

Zhang W., Gao Y., Huang J., Zhang G., Andreev Y. M., Grechin S. G., Lanskii G. V.

Materials Science Poland

|

2015

|

Vol. 33, No. 2

391--396

EN

The thermo-optic coupling process of second harmonic generation was numerically simulated in ZnGeP2 crystals pumped by a pulsed CO2 laser at the wavelength of 9.6 mu m, under the strong and weak cooling conditions. The conversion efficiencies, temperature distributions were calculated during the evolution of the thermo-optic coupling. The results showed that the thermo-optic coupling was weak in the strong cooling condition, which nearly did not disturb the conversion processes and temperature distribution, while in the weak cooling case, the temperature distribution showed a great influence on the conversion efficiency and light intensity. Finally, it was found that compensation of the phase mismatch induced by the thermal effect can well recover the conversion efficiency.

13

A new approach to robust ﬁnite-time H∞ control of continuous-time Markov jump systems

Yan S., Shen M., Fei S., Zhang G.

Control and Cybernetics

|

2015

|

Vol. 44, no. 2

211--231

EN

This paper studies the robust ﬁnite-time H∞ state feedback control problem of continuous-time Markov jump systems (MJSs) subject to norm bounded uncertainties. Transition probabilities are allowed to be known, uncertain with known bounds or unknown. Based on the continuous transition probability property and the developed slack variable technique, Lyapunov variables are separatek from unknown transition probabilities and system matrices. With these separations, a relaxed method for robust ﬁnite-time H∞ controller design is proposed in terms of linear matrix inequalities (LMIs). Numerical examples are given to illustrate the eﬀectiveness of and the beneﬁt from the proposed method.

14

Identification and differentiation of major flavonoids in two kinds of Epimedium extracts and rat plasma by rapid-resolution liquid chromatography combined with time-of-flight mass spectrometry

Lv L., Zhao L., Wang X., Zhang H., Zhu Z., Chai Y., Zhang G.

Acta Chromatographica

|

2015

|

Vol. 27, no. 2

331--353

EN

Epimedium pubescens Maxim. and Epimedium koreanum Nakai. are two common and confused species of Herba Epimedii in Chinese Pharmacopoeia 2010 edition. Different species and growing conditions lead to chemical differences between the two species which may result in the improper clinical usage. In this work, a new method based on rapid-resolution liquid chromatography combined with time-of-flight mass spectrometry (RRLC/TOFMS) has been developed for identification and differentiation of major flavonoids in two kinds of Epimedium extract and rat plasma. The compounds were identified effectively based on the accurate extract masses and formulae acquired by RRLC/TOFMS. The fragmentation rules deduced by collision-induced dissociation (CID) were successfully implemented in distinguishing some of the isomers, further validating the results. By using the combined analytical techniques, a total of 40 major flavonoids in extracts of two kinds of Epimedium were identified within 30 min, including 31 common components and 9 characteristic components. After oral administration, three prototype compounds in rat plasma were detected by comparing the constituents measured in vitro with those in vivo, and five metabolites were identified by contrasting the fragmentation rules. The identification and structural elucidation of the chemical constituents provided essential data for further pharmacological and clinical studies on different species of Epimedium.

15

Robust Cepstrum Radio Frequency Fingerprint Transformed from BPSK Signal

Yuan H., Bao Z., Xu C., Zhang G.

Przegląd Elektrotechniczny

|

2013

|

R. 89, nr 1b

193--195

EN

Identifying wireless devices based on Radio Frequency fingerprint (RFF) is a promising physical layer security methodology. One practical issue is the robustness of RFF affected by wireless multi-path channels, etc. Proposed is a kind of RFF with robustness for identifying digital BPSK transmitters. The cepstrum of the received BPSK signal is obtained and then low-pass filtered, the result signal is mainly determined by device impulse response, and thus is robust. The proposed fingerprint can be used in the fusion identification of BPSK wireless transmitters.

PL

W artykule opisano sposób radiowej identyfikacji urządzeń bezprzewodowych, o bezpiecznej identyfikacji cyfrowych nadajników BPSK. Uzyskane cepstrum odebranego sygnału BPSK, poddawane jest filtracji dolno-przepustowej, co w efekcie daje sygnał wyznaczony przez odpowiedź impulsową urządzenia. Opracowany algorytm można wykorzystać w rozpoznaniu łączenia się nadajników BPSK.

16

Optimization model of the Joint operation of Pumped-Storage Hydro Plant and Wind Farm: Considering the Imbalances of Wind Power Output

Song W., Zhang K., Li L., Zeng M., Zhang G.

Przegląd Elektrotechniczny

|

2013

|

R. 89, nr 3b

207--211

EN

Since the future energy production of wind farm is uneasy to be precisely predicted, the integration of wind power into electric power system has been a difficult problem for many years. Recently, the widely emerged pumped-storage hydro plant can be used to balance the unstable output of wind farm, because the pumped-storage hydro plant can adjust its production to compensate wind power prediction errors. In this paper, a joint operation model between the wind farm and pumped-storage hydro plant is proposed. In this mode, there are two targets for the system: 1) maximizing the daily revenue of pumped-storage hydro plant; 2) partially compensating the deviations resulted from wind power output imbalances. Then we analyzed the economic benefits of pumped-storage hydro plant in the condition of both independent operation and joint operation. Finally, the model is applied in the actual operation of pumped-storage hydro plant. From the case study we can see that power incomes of pumped-storage hydro plant alone is reduced under joint operation model, while the comprehensive economic effect has actually increased in response to the stable output of wind power.

PL

W artykule przedstawiono model współpracy farmy wiatrowej z elektrownią szczytowo-pompową. Wspólna praca tych jednostek wynika z niestabilności energii wiatrowej i pozwala na jej redukcję. Zbudowany model umożliwia realizację dwóch celów: maksymalizacji dziennego zysku z magazynowania energii w elektrowni oraz częściowe ograniczenie wahań wytwarzanej energii, wynikające z niestabilności wiatru. Dokonano także analizy ekonomicznej zysków z pracy jednostek w trybach współpracy oraz pracy niezależnej. Przeprowadzono weryfikację opracowanego modelu na rzeczywistych danych.

17

Environmental and Economic Dispatch Model for Smart Microgrid Based on Shuffled Frog Leap Algorithm Optimized by Random Nelder Mead

Zhong Q., Xue S., Wang Z., Duan J., Zeng M., Zhang G.

Przegląd Elektrotechniczny

|

2013

|

R. 89, nr 3b

147--151

EN

As more and more distributed generation resources are integrated into the grid through smart micro-grid, achieving a more economic and better responsive distributed generation dispatch is of great importance. Economic and environmental characteristics of distributed generation are synthetically combined in a dispatch model with objective function of minimum generation cost and emission cost in this paper, and also a novel algorithm Shuffled Frog Leap Algorithm (SFLA) optimized by random Nelder Mead (RNM) model was proposed to solve the economic and environmental problem. At last, the differences in generation cost and Computation time of RNM-SFLA, Genetic Algorithm (GA), Evolutionary Programming (EP) and Shuffled Frog Leap Algorithm (SFLA) are compared with a numerical example, verifying the feasibility and advancement of environmental and economic dispatch model based on RNM-SFLA.

PL

W artykule przedstawiono model przesyłu energii elektrycznej w systemie elektroenergetycznym, mający na celu minimalizację kosztów wytwarzania i przesyłu energii. Zaproponowano także nowy algorytm SFL (ang. Shuffled Frog Leap), który został zoptymalizowany metodą Nelder’aa-Mead’a. Algorytm ma zastosowanie w rozwiązywaniu zagadnień ekonomicznych i środowiskowych. Przeprowadzona została analiza porównawcza opisanego modelu.

18

Novel robust control design for unstable systems with dual pole and dual zero

Zhang X., Zhang G.

Control and Cybernetics

|

2013

|

Vol. 42, no. 3

613--625

EN

In this note, a novel robust control design for a class of unstable systems with dual pole and dual zero is addressed. In the algorithm, αfeedback node was moved from the interior of the controlled plant to its right-hand side. Then, the closed-loop gain shaping algorithm was used to design the feedback transfer function. Consequently, controller and the controlled plant have clear physical meaning and are easily tuned. Simulation results show that the control effects are better than for the previous modification, the system can have rapid settling time with no overshoot, zero steadystate error and satisfactory robust stability to model perturbation and disturbance. The method has the advantages of simple and efficient design, and it was also successfully applied to control static unstable missile.

19

The Hierarchical-Cluster Topology Control Strategy of InterPlaNetary Internet Backbone based on Libration Points

Jiang Y., Li G., Zhang G., Yang S.

Przegląd Elektrotechniczny

|

2012

|

R. 88, nr 4a

271-276

EN

The concept of InterPlaNetary (IPN) Internet was proposed by National Aeronautics and Space Administration (NASA). The IPN Internet could provide Internet-like services crossing interplanetary distances in support of deep space exploration, which includes backbone network, access network, and planetary network. The IPN backbone topology control strategy based on Libration points was studied in this paper. Firstly, the location and stability of Libration point is simulated by celestial mechanics. Secondly, a novel Hierarchical-Cluster model of IPN backbone network is proposed to simplify topology design. Then Intra-Cluster Link and Inter-Cluster Link are analyzed in detail. Finally, the optimal handover moment is gotten by critical angle which to use relay theory, and the total number of handover times is calculated within a relative period between Uranus and Neptune cluster.

PL

Koncepcja interplanetarnego Internetu IPN została zaproponowana przez NASA. W artykule omówiono strategię kontroli topologii szkieletu bazującą, na punkcie Libration. Na wstępie przeanalizowano stabilność systemu a następnie model hierarchiczny klastrów. Wreszcie analizowano przełączenie połączeń między stacjami bazowymi – handover.

20

Speech Emotion Recognition Using Hybrid Generative and Discriminative Models

Huang Y., Zhang G., Dong F., Li Y., Da F.

Przegląd Elektrotechniczny

|

2012

|

R. 88, nr 3b

105-108

EN

In this paper, we use Sequential Forward Selection to select 8 dimensional frame-level features from the total 69 dimensional features, and we reduce the dimensions of utterance-level eigenvectors from 63 to 12 by fisher discriminant. Then, two kinds of GMM multidimensional likelihoods are proposed for hybrid generative and discriminative models. Experimental results on Berlin emotional speech databases show that the GMM-MAP/SVM series hybrid model is the optimal Hybrid Generative and Discriminative Models, with the recognition rate up to 85.1%.

PL

W artykule zaprezentowano system wykrywania emocji w głosie na podstawie modelu dyskryminacyjnego. Zaprezentowano badania skuteczności system na przykładzie bazy danych Berlin.