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991.
Burdonov I. B. Vinarskii E. M. Yevtushenko N. V. Kossatchev A. S. 《Programming and Computer Software》2021,47(7):505-514
Programming and Computer Software - This paper investigates the implementation of virtual networks on the SDN data plane modeled by a graph of physical connections between network nodes. A virtual... 相似文献
992.
Neural Computing and Applications - The impact of viscous dissipation in hybrid nanofluid plays a prominent role in industrial applications, for instance, in polymer processing flows and... 相似文献
993.
Matthew L. Bolton Ellen J. Bass Radu I. Siminiceanu 《International journal of human-computer studies》2012,70(11):888-906
Breakdowns in complex systems often occur as a result of system elements interacting in unanticipated ways. In systems with human operators, human–automation interaction associated with both normative and erroneous human behavior can contribute to such failures. Model-driven design and analysis techniques provide engineers with formal methods tools and techniques capable of evaluating how human behavior can contribute to system failures. This paper presents a novel method for automatically generating task analytic models encompassing both normative and erroneous human behavior from normative task models. The generated erroneous behavior is capable of replicating Hollnagel's zero-order phenotypes of erroneous action for omissions, jumps, repetitions, and intrusions. Multiple phenotypical acts can occur in sequence, thus allowing for the generation of higher order phenotypes. The task behavior model pattern capable of generating erroneous behavior can be integrated into a formal system model so that system safety properties can be formally verified with a model checker. This allows analysts to prove that a human–automation interactive system (as represented by the model) will or will not satisfy safety properties with both normative and generated erroneous human behavior. We present benchmarks related to the size of the statespace and verification time of models to show how the erroneous human behavior generation process scales. We demonstrate the method with a case study: the operation of a radiation therapy machine. A potential problem resulting from a generated erroneous human action is discovered. A design intervention is presented which prevents this problem from occurring. We discuss how our method could be used to evaluate larger applications and recommend future paths of development. 相似文献
994.
I. A. Astafyev 《Pattern Recognition and Image Analysis》2012,22(1):164-167
This paper proposes a method of finding the threshold value for segmenting objects of a priori known form. The problem is
formulated as an optimization problem. The segmentation of the human pupil (the first stage of the iris segmentation in the
iris recognition process) is given as an example of implementing the approach. 相似文献
995.
A. D. Roy’s safety-first (SF) approach to financial portfolio optimization is improved. Safety first means the minimization
of the probability of negative returns. The improvement concerns a better estimation of the negative return probabilities
by means of mean excess return risk functions. The search for the optimal SF-portfolio is similar to Roy’s geometric method
but the efficient frontier is different. In case of a finite number of scenarios, the SF-portfolio selection problem is reduced
to a mixed linear Boolean programming problem. 相似文献
996.
S. N. Evdokimov S. I. Klimanov A. N. Korchagin E. A. Mikrin Yu. G. Sikharulidze 《Journal of Computer and Systems Sciences International》2012,51(6):802-817
Results concerning the terminal guidance algorithm at the reentry of the descent module into the Earth atmosphere are presented. This algorithm simultaneously eliminates predicted deviations in the downrange and crossrange directions. The restriction on the tolerable load factor n ?? 3 is taken into account. Three reentry angles are analyzed: the medium angle ?1.5°, the steep angle ?1.9°, and the flat angle ?1.2°. The motion of the descent module is considered in the disturbed Earth atmosphere represented by the TsNIIMash model. This model includes variations of the atmosphere density and the wind field. It is demonstrated that, depending on the reentry angle, the proposed algorithm guarantees the downrange maneuver zone in the range 1240?C1890 km and the crossrange maneuver zone of 210?C220 km on one side. The maximum guidance error at the altitude of 1 km does not exceed 0.8 km, and the average error is 0.1 km. The algorithm uses up to three bank angle reversals and uses the numerical prediction of the remaining part of the trajectory when choosing the guidance parameters. The concept of the automatic adjustment of the bank angle reference function depending on the entry angle and the prescribed distance to the target point in the maneuver zone is formulated. 相似文献
997.
S. M. Popov V. V. Voloshin I. L. Vorobyov G. A. Ivanov A. O. Kolosovskii V. A. Isaev Y. K. Chamorovskii 《Optical Memory & Neural Networks》2012,21(1):45-51
Temperature band of ordinary telecommunication optical fibers is −60...85°C. The developing fiber optic sensors which can
work at higher temperatures, required to develop metal coated optical fibers. The Purpose of the work is a researching additional
optical loss of copper alloy coated optical fibers which were drawn from low hydroxyl group contamination preforms at temperatures
20...800°C. It is reached that metal coated optical fiber worked at temperature 700°C for 7 hours, while the optical losses
changed from 2 to 3 dB/km at the wavelength of λ = 1300 nm. It is not observed intensive growth of optical losses on hydroxyl
groups at 800°C, which was observed in metal coated optical fiber when it was heated at 700°C. 相似文献
998.
Based on new constructive means of the theory of R-functions, new approaches are proposed to the construction of equations for objects of fractal geometry. Equations for some of the most well-known fractals, namely, the Koch curve, snowflake, and cross, Sierpinski carpet, Levy fractal, and Pythagoras tree are presented. 相似文献
999.
This article presents an approach for the automatic recognition of non-native speech. Some non-native speakers tend to pronounce
phonemes as they would in their native language. Model adaptation can improve the recognition rate for non-native speakers,
but has difficulties dealing with pronunciation errors like phoneme insertions or substitutions. For these pronunciation mismatches,
pronunciation modeling can make the recognition system more robust. Our approach is based on acoustic model transformation
and pronunciation modeling for multiple non-native accents. For acoustic model transformation, two approaches are evaluated:
MAP and model re-estimation. For pronunciation modeling, confusion rules (alternate pronunciations) are automatically extracted
from a small non-native speech corpus. This paper presents a novel approach to introduce confusion rules in the recognition
system which are automatically learned through pronunciation modelling. The modified HMM of a foreign spoken language phoneme
includes its canonical pronunciation along with all the alternate non-native pronunciations, so that spoken language phonemes
pronounced correctly by a non-native speaker could be recognized. We evaluate our approaches on the European project HIWIRE non-native corpus which contains English sentences pronounced by French, Italian, Greek and Spanish speakers. Two cases are
studied: the native language of the test speaker is either known or unknown. Our approach gives better recognition results
than the classical acoustic adaptation of HMM when the foreign origin of the speaker is known. We obtain 22% WER reduction
compared to the reference system. 相似文献
1000.
Jose Saldana Julián Fernández-Navajas José Ruiz-Mas Jenifer Murillo Eduardo Viruete Navarro José I. Aznar 《Computer Networks》2012,56(7):1893-1919
This work presents a study of RTP multiplexing schemes, which are compared with the normal use of RTP, in terms of experienced quality. Bandwidth saving, latency and packet loss for different options are studied, and some tests of Voice over IP (VoIP) traffic are carried out in order to compare the quality obtained using different implementations of the router buffer. Voice quality is calculated using ITU R-factor, which is a widely accepted quality estimator. The tests show the bandwidth savings of multiplexing, and also the importance of packet size for certain buffers, as latency and packet loss may be affected. The customer’s experience improvement is measured, showing that the use of multiplexing can be interesting in some scenarios, like an enterprise with different offices connected via the Internet. The system is also tested using different numbers of samples per packet, and the distribution of the flows into different tunnels is found to be an important factor in order to achieve an optimal perceived quality for each kind of buffer. Grouping all the flows into a single tunnel will not always be the best solution, as the increase of the number of flows does not improve bandwidth efficiency indefinitely. If the buffer penalizes big packets, it will be better to group the flows into a number of tunnels. The router processing capacity has to be taken into account too, as the limit of packets per second it can manage must not be exceeded. The obtained results show that multiplexing is a good way to improve customer’s experience of VoIP in scenarios where many RTP flows share the same path. 相似文献