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31.
This paper proposes a scheme for online voltage stability monitoring using an enhanced Radial Basis Function Network (RBFN). A single RBFN is used to predict MW margins for different contingencies. A sequential learning strategy is used along with a regularization technique to design the RBFN and the weights in the output layer are determined by using linear optimization. The proposed network can be adapted with changing operating scenario of the power system. A network pruning strategy is used to limit the growth of the network size due to adaptive training. The proposed scheme is applied on the New England 39-bus power system model. 相似文献
32.
Chakrabarti Saikat Chandrasekhar Santosh Singhal Mukesh Calvert Kenneth L. 《Parallel and Distributed Systems, IEEE Transactions on》2009,20(7):1059-1072
Aggregate signatures can be a crucial building block for providing scalable authentication of a large number of users in several applications like building efficient certificate chains, authenticating distributed content management systems, and securing path vector routing protocols. Aggregate signatures aim to prevent resources (signature and storage elements, and computation) from growing linearly in the number of signers participating in a network protocol. In this paper, we present an efficient and scalable quasi-aggregate signature scheme, {rm CLFSR}- {rm QA}, based on third-order linear feedback shift register (cubic LFSR) sequences that can be instantiated using both XTR and GH public key cryptosystems. In the proposed {rm CLFSR}-{rm QA} construction, signers sign messages sequentially; however, the verfier need not know the order in which messages were signed. The proposed scheme offers constant length signatures, fast signing, aggregation, and verification operations at each node, and requires the least storage elements (public keys needed to verify the signature), compared to any other aggregate signature scheme. To the best of our knowledge, {rm CLFSR}- {rm QA} is the first aggregate signature scheme to be constructed using LFSR sequences. We believe that the {rm CLFSR}- {rm QA} signature scheme can be catalytic in improving the processing latency as well as reducing space requirements in building secure, large-scale distributed network protocols. We perform extensive theoretical analysis including correctness and security of {rm CLFSR}- {rm QA} and also present a performance (computation and communication costs, storage overhead) comparison of the proposed scheme with well-known traditional constructions. 相似文献
33.
Chraplyvy A.R. Liou K.Y. Tkach R.W. Eisenstein G. Jhee Y.K. Koch T.L. Anthony P.J. Chakrabarti U.K. 《Electronics letters》1986,22(2):88-90
An external-cavity laser consisting of a 1.5 ?m-wavelength antireflection-coated DFB laser chip, a microscope objective and a mirror provides a stable, single-frequency, narrow-linewidth (?f=40 kHz) output. Because the laser operates in the strong feedback regime, it is immune to external optical perturbations. Single-longitudinal-mode operation is maintained by the DFB grating, and the linewidth is reduced by the extended passive cavity. 相似文献
34.
The problem of diffraction of a plane electromagnetic wave by a dielectric half-plane is reconsidered for solution by utilizing a set of recently developed approximate boundary conditions and the Wiener-Hopf technique. It is observed from the present solution of the problem that reflected waves cease to exist if the angle of incidence takes up the valuetan^{-1}(1/n) wheren represents the refractive index of the material of the half-plane under consideration. Expression for the diffracted far field is obtained by using a modification of the saddle point method, and numerical values of the diffraction coefficients are presented in the form of a table for a special value of the refractive indexn and for different values of the parameterkh, h representing the (small) thickness of the half-plane andk the wavenumber. 相似文献
35.
Samar J. Kalita Robert Fleming Himesh Bhatt Brian Schanen Ratna Chakrabarti 《Materials science & engineering. C, Materials for biological applications》2008,28(3):392-398
Controlling the strength-loss rate during biodegradation is a bottleneck in developing viable resorbable ceramic implants. Resorbable beta-tricalcium phosphate (β-TCP) bioceramic is known for its excellent biocompatibility. However, it exhibits poor sinterability and poor flexural strength. Here, we improved sintering behavior and biaxial flexural strength of β-TCP bioceramic without altering its biocompatibility by introducing multi-oxide sintering additives, in small quantities. These additives could also tailor the rate of resorption and hardness deterioration of β-TCP. A range of additives were prepared and introduced into β-TCP powder. Resultant powders were uniaxially pressed and sintered at 1250 °C, in air. Considerable improvement in densification (up to 33%) and biaxial flexural strength (up to 43%) were achieved. X-ray powder diffraction (XRD) analysis confirmed that the additives didn't alter the phase purity. In vitro cytotoxicity and biocompatibility analyses were performed using a prostate cancer cell-line. Results showed that the doped and pure β-TCP structures were non-toxic and biocompatible. 相似文献
36.
Organizations face increased pressures to continually advance knowledge and new technologies long-term success and prosperity. University research centers offer important interorganizational linkages for industry-university collaboration, conducive for advancing knowledge and new technologies. This study examined industry's strategic objectives for establishing relationships with university research centers. As a result of this multimethod exploratory field study, the authors have identified three clusters of industrial firms with different strategic objectives: collegial players, aggressive players, and targeted players. Collegial players are predominately large firms working with university research centers on topics of interest to the firm which are perceived to have long-term value rather than the promise of immediate commercial opportunities. Aggressive players are a mix of both large and small firms employing relationships with university research center primarily to develop and commercialize a wide range of marketable products and services. Targeted players are often smaller firms largely interested in using their relationships with university research centers to address specific needs central to their business. They conclude this paper by discussing the implications of these findings for both industrial firms and universities 相似文献
37.
Rupsankar Chakrabarti & Badiveddy Madhusudana Rao 《International Journal of Food Science & Technology》2008,43(1):179-184
The annual inland fish production in India is 3.2 million tonnes and above. Aquaculture is around 80% of total inland fish production. The enhanced aquaculture production demands alternate processing methods for better utilisation of the farmed fish. Cirrhinus mrigala is one of the dominated species among cultured Indian major carps, but rated with lowest price. Fish meat with good gel‐forming capacity is a prerequisite in the production of fast‐moving fabricated analogue product. Cirrhinus mrigala had the highest gel strength, i.e. 435 gcm of its fresh meat in comparison with other carps. Apart from the highest protein and salt‐soluble protein nitrogen content in fresh C. mrigala meat, this article also reports that the presence of the darkest thick band of myosin heavy chain and actin in the polyacrylamide gel electrophoresis pattern of salt‐soluble extract of C. mrigala might be another possible reason for the highest gel strength in comparison with other carps. Cirrhinus mrigala contained white meat around 90%. This carp could be suitably used in the preparation of high‐valued fabricated analogue product. 相似文献
38.
A theoretical analysis of mass transfer effects in ethyl cellulose manufacture has been reported. This is the first model to describe a complex fluid–solid reaction in the presence of two immiscible liquids. The model derived here can be used to evaluate the dependency of the overall rate on different parameters incorporating the multiphase mass transfer effects. 相似文献
39.
In the present study, an Enterococcus gallinarum strain was isolated from effluent treatment plant of a textile industry based on its ability to decolourize C.I. Direct Black 38 (DB38), a benzidine-based azo dye. Effects of dye concentration and medium composition on dye decolourization were studied. The strain was found to decolourize DB38 even under aerobic conditions. Kinetics of DB38 decolourization was also examined, and V(max) and K(s) of decolourization were found to be higher in Luria broth (12.8 mg l(-1)h(-1) and 490.6 mg l(-1)) than in minimal medium (4.09 mg l(-1)h(-1) and 161.84 mg l(-1)). However, decolourization rate/biomass was found to be higher in minimal medium than in Luria broth, indicating greater decolourization efficiency of biomass in the former. The study also revealed biodegradation of DB38 to benzidine and its further deamination to 4-aminobiphenyl (4-ABP) by the culture. Ammonia released during this process was used as nitrogen source for growth of the culture. 相似文献
40.