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71.
Chattopadhyay I. Ray A. 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2009,39(6):1505-1515
This paper formulates a self-organization algorithm to address the problem of global behavior supervision in engineered swarms of arbitrarily large population sizes. The swarms considered in this paper are assumed to be homogeneous collections of independent identical finite-state agents, each of which is modeled by an irreducible finite Markov chain. The proposed algorithm computes the necessary perturbations in the local agents' behavior, which guarantees convergence to the desired observed state of the swarm. The ergodicity property of the swarm, which is induced as a result of the irreducibility of the agent models, implies that while the local behavior of the agents converges to the desired behavior only in the time average, the overall swarm behavior converges to the specification and stays there at all times. A simulation example illustrates the underlying concept. 相似文献
72.
Rup Narayan Ray Debashis Chatterjee Swapan Kumar Goswami 《Applied Soft Computing》2009,9(4):1315-1320
Harmonic elimination problem in PWM inverter is treated as an optimization problem and solved using particle swarm optimization (PSO) technique. The derived equation for computation of total harmonic distortion (THD) of the output voltage of PWM inverter is used as the objective function in the PSO algorithm. The objective function is minimized to contribute the minimum THD in the voltage waveform and the corresponding switching angles are computed. The method is applied to investigate the switching patterns of both unipolar and bipolar case. While minimizing the objective function, the individual selected harmonics like 5th, 7th, 11th and 13th can be controlled within the allowable limits by incorporating the constraints in the PSO algorithm. The results of the unipolar case using five switching angles are compared with that of a recently reported work and it is observed that the proposed method is effective in reducing the voltage THD in a wide range of modulation index. The simulated results are also validated through suitable experiments. 相似文献
73.
Sandip Ghosh Sarit K. Das Goshaidas Ray 《International Journal of Control, Automation and Systems》2009,7(2):311-317
Adaptive stabilization of a class of linear systems with matched and unmatched uncertainties is considered in this paper.
The proposed controller indeed stabilizes the uncertain system for any positive values of its non-adaptive gain that may be
tuned to enhance dynamic response of system. The performance of uncertain system along with the Algebraic Riccati Equation
that arises from the adaptive stabilizing controller is now formulated as a multi-objective Linear Matrix Inequality optimization
problem. The decay rate and a factor governing the ultimate bound of the system states are considered to characterize the
closed loop system performance. Finally, the effectiveness of the proposed controller is illustrated via stabilizing a mass-spring
system.
Recommended by Editorial Board member Gang Tao under the direction of Editor Young Il Lee. The authors would like to thank
the reviewers for their valuable comments and suggestions that have improved the quality of this paper.
Sandip Ghosh received the B.E. in Electrical Engineering from Bengal Engineering College (D.U.), Howrah, and Master in Control System
Engineering from Jadavpur University, Kolkata, India, in 1999 and 2003 respectively. Presently he is pursuing the Ph.D. degree
at Indian Institute of Technology, Kharagpur, India. His research interests include adaptive control, robust control and control
of time-delay systems.
Sarit K. Das is a Professor of Electrical Engineering Department, Indian Institute of Technology, Kharagpur, India. He received the Ph.D.
degree in 1985 from the same department. His research interests include design of periodic controller, decoupling of multivariable
systems, modeling and robust control of complex systems.
Goshaidas Ray is a Professor of Electrical Engineering Department, Indian Institute of Technology, Kharagpur, India. He received the Ph.D.
degree in 1982 from Indian Institute of Technology Delhi, India. His research interests include modeling, estimation, model-based
control, intelligent control, robotic systems and distributed control systems. 相似文献
74.
This paper presents a large anisotropic damage theory of continuum damage mechanics. It is developed via a new hypothesis of incremental complementary elastic energy equivalence. This hypothesis is more versatile and accurate if compared to the original hypothesis of total complementary energy equivalence. To model the large damage, we assumed that it occurs as a series of incremental small damage. An expression for the damage effect tensor M(D) for large damage is derived. It is shown that when the damage is small, that is, D
i1, the proposed large damage theory reduces to the small damage model of Chow and Wang [1]. To demonstrate this large damage theory, it is applied to model the following cases: (a) uniaxial tension, (b) pure torsion and (c) elastic perfectly-plastic material behavior. In all three cases, the results clearly show that when the damage is small, Chow and Wang's model is recovered. However, for large damage, there are significant differences in predictions. Since this large damage theory is formulated on the basis of the incremental complementary energy, it is applicable to a wider range of problems. 相似文献
75.
Kindergartens of age group 3-5 years, a distinct and small subgroup of Indian schoolchildren, need special emphasis on human factors. The paper presents the results of an anthropometric survey conducted on schoolchildren. These data, previously lacking in India, can be of benefit for the designers of kindergartens. A set of 81 different body dimensions was taken from a sample of 198 children of age group 3-4 years and 4.1-5 years. Simple anthropometric techniques were used to collect the data. Statistical analyses of the data have been presented in a tabular form for designers as well as for non-technical users. It is emphasized that such data have to be developed at the national level, including every ethnic group, or on a regional basis. Designers, manufacturers and importers of goods should have access to these data. 相似文献
76.
Jian Qiao Jiangtao Di Susheng Zhou Kaiyun Jin Sha Zeng Na Li Shaoli Fang Yanhui Song Min Li Ray H. Baughman Qingwen Li 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(38)
Artificial muscles are reported in which reduced graphene oxide (rGO) is trapped in the helical corridors of a carbon nanotube (CNT) yarn. When electrochemically driven in aqueous electrolytes, these coiled CNT/rGO yarn muscles can contract by 8.1%, which is over six times that of the previous results for CNT yarn muscles driven in an inorganic electrolyte (1.3%). They can contract to provide a final stress of over 14 MPa, which is about 40 times that of natural muscles. The hybrid yarn muscle shows a unique catch state, in which 95% of the contraction is retained for 1000 s following charging and subsequent disconnection from the power supply. Hence, they are unlike thermal muscles and natural muscles, which need to consume energy to maintain contraction. Additionally, these muscles can be reversibly cycled while lifting heavy loads. 相似文献
77.
MXene Yarn Supercapacitors: High‐Performance Biscrolled MXene/Carbon Nanotube Yarn Supercapacitors (Small 37/2018)
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78.
79.
JG Ray 《Canadian Metallurgical Quarterly》1998,53(7):450-455
Synthetic 1-deamino-8-D-arginine-vasopressin (DDAVP) is used in the management of diabetes insipidus (DI). We conducted a systematic literature review of DDAVP use during pregnancy, with particular attention to its safety for both mother and infant. Studies were identified through Ovid MEDLINE from 1976 to July 1997 using the combined terms "desmopressin," "DDAVP," and "pregnancy". Review articles and published letters were also explored. One hundred one articles were retrieved, of which 20 met all the inclusion criteria. Included in the 20 articles were 53 cases with the use of DDAVP for the management of DI. The therapeutic daily dose of DDAVP was approximately 29 micrograms intranasally (range 7.5-100 micrograms), with adequate DI control observed. Three of 14 women with sufficient information developed preeclampsia, a nonsignificant difference from the expected rate of 5 percent (the Fisher exact test, 2-P = .08). The mode of delivery was defined for 22 cases, with 16 uneventful vaginal births, and six cesarean delivery. There was no evidence of a drug interaction among the five women who received both DDAVP and intravenous oxytocin. Information was available on 49 live births born to DI mothers on DDAVP. The mean gestational age at delivery was 37.4 weeks (SD 1.3 weeks), with an estimated mean birth weight of 2963.8 gm (range 2000-4420 gm). Forty-three offspring were reported as healthy (event rate 87.8 percent; 95 percent CI 77.2-95.3 percent). Of the remaining six infants, one developed DI at 18 months of age; a second was under 2500 gm at birth, but survived; the third developed hypotonia and failure to thrive at 21 months, two others had Down syndrome; and the sixth died of severe cardiac anomalies. Similar data were seen among the 41 infants whose mothers had used DDAVP throughout pregnancy. In conclusion, DDAVP use during pregnancy seems to be safe for both mother and child. Delivery does not seem to be augmented by its use, nor are there likely any associated adverse neonatal effects. A large database of DDAVP use during pregnancy is needed to confirm these findings. 相似文献
80.
The increasing need for active and accessible learning in the inclusive knowledge society drives the demand for e-learning
that engages users much more effectively than ever before. In this context, it is crucial to conduct research that embraces
innovation in user sensitive design, or else influential individual user differences may be overlooked. The objective of this
paper is to explore the creation of successful e-learning systems that are able to increase users’ learning performance and
enhance their personal learning experiences. The paper reports two converging and complimentary approaches, namely case studies
and experimentation. First, case studies are used to explore the extent to which effective e-learning systems comply with
eight specific factors. Of the eight, accessibility, individual differences and student modeling turn out to be the weakest
points in current practice. Second, an empirical study investigates the influences of user individual user differences on
users’ learning outcomes in an e-learning environment. The experiment found that individual differences in motivation to learn
and expectations about e-learning significantly impacted users’ learning achievements. Third, based on these studies, improvements
in research methodology are identified towards greater consideration of user sensitive research issues, thus enabling us to
outline improved experimental procedures. Further experiment results should provide us with better insights into the arguments
needed to carefully assess benefits of developing and involving a user model in an e-learning application. Consequently, evaluation
and justification could now encompass both system performance as well as user performance. 相似文献