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71.
Biprodas Dutta Jugdersuren Battogtokh David Mckewon Igor Vidensky Neilanjan Dutta Ian L. Pegg 《Journal of Electronic Materials》2007,36(7):746-752
NaCo2O4 has one of the highest figures of merit among all ceramic thermoelectric materials. Because of its large thermopower and
low resistivity, the ceramic oxide NaCo2O4 is a promising candidate for potential thermoelectric applications. NaCo2O4 is, moreover, a ceramic compound with high decomposition temperature and chemical stability in air and it does not contain
any toxic elements. Like all 3-d transition ions, Co ions have multiple spin and oxidation states. In this investigation,
thermopower and electrical conductivity of NaCo2O4 as a function of substitution of Co by Fe ions were measured. Fe substitution for Co causes resistivity to increase, whereas
the Seebeck coefficient remained nearly invariant, especially above 330 K.
An erratum to this article can be found at 相似文献
72.
Tao Zhang Eric van den Berg Sunil Madhani Ashutosh Dutta Shantidev Mohanti 《Wireless Networks》2007,13(5):617-633
Mobile users and devices want to discover and share a growing range of information as the processing and storage capabilities
of mobile devices grow. For example, users want to discover nearby networks, and location-based or time-sensitive user information
contents. A mobile device may want to discover neighboring networks and the parameters required to access these networks so
that it can intelligently decide which networks to use next, and use its existing network connection to authenticate with
selected neighboring networks before it moves into the coverage areas of the selected networks. This can significantly reduce
handoff delays. Existing service discovery frameworks are not effective for such neighboring network discovery or for discovering
dynamic, location- or time-sensitive user information contents. This paper describes and evaluates a new approach—Mobile Information
Services enabled by Mobile Publishing (MIS-MP)—for real time collection, discovery, and sharing of network and user information.
With MIS-MP, mobiles take full advantage of the wealth of information they can accumulate during their routine mobility and
use of networks to help each other to discover the information they want when and where they want it. This is accomplished
by mobiles publishing the information they collect about the networks they visited, and the user information contents they
learned or used, to make the information available to other mobiles. This paper presents analytical models and simulation
results to evaluate the feasibility and performance of MIS-MP. It also describes a testbed implementation of MIS-MP and some
of the lessons we learned.
Tao Zhang is Director of Mobile Networking Research Group at Telcordia Technologies, Piscataway, New Jersey, USA. He develops and directs
research and advanced development programs in mobile networking and applications, including mobility and applications across
heterogeneous radio networks, mobile information services, vehicular networking, mobile peer-to-peer applications, sensor
networking and applications, and collaborative networking .Dr. Zhang’s work has led to several new commercial products. He
co-authored the book “IP-Based Next Generation Wireless Networks” published by John Wiley & Sons in 2004. He initiated the International Conference on Collaborative Computing: Networking,
Applications, and Worksharing (CollaborateCom), and has been serving in various roles for it. Dr. Zhang holds 4 U.S. patents,
with over 25 more pending. He received the 2000 Telcordia CEO Award (for most exceptional teams and individuals who have achieved
a significant business success) and 2002 SAIC’s Executive Science and Technology Council Publication Prize.
Eric van den Berg received his Ph.D. in Applied Mathematics from Cornell University in 1999. After obtaining his degree, he joined Telcordia
Technologies, where he is a Research Scientist in Applied Research Department. His research interests include traffic modeling
and performance analysis of IP- and wireless networks. He received the 2000 Telcordia CEO Award (for most exceptional individuals
and teams who have achieved a significant business success) and the 2002 SAIC Executive Science and Technology Council Publication
Prize.
Sunil Madhani is a Distinguished MTS with Motorola where he manages the IP Realization team in Mobile Device Technology Office. He aims
at working on unconventional and disruptive IP technologies. His current research focus is on convergent networks, dynamic
mobility management and fast handoff in secured/seamless wireless LAN/WAN roaming. His past research includes registration/configuration
protocols in wireless environment, application layer mobility management, secured Mobile IP, managed DOS attack sensor and
TCP/IP boosters. Sunil Madhani holds MS (2002) in Engineering Management & System from Columbia University and MS (1997) in
Computer Science from State University of New York. 相似文献
73.
S. C. Dutta Roy D. K. Bhargava 《International Journal of Circuit Theory and Applications》1977,5(3):235-238
For any realization of a network function F(s) = N(s)/D(s), the sensitivities that can be most readily calculated are those of the coefficients in N(s) and D(s). A simple relationship is derived that enables one to calculate the root (pole and zero) sensitivities of F(s) in terms of the coefficient sensitivities. The root sensitivities, in turn, enable one to calculate the root pair Q and root frequency sensitivities, which can be used to characterize and compare different realizations of F(s). Application to 3rd- and 4th-order filters reveals formulations that are more elegant than those already known in the literature. 相似文献
74.
The problem of obtaining a single “consensus” clustering solution from a multitude or ensemble of clusterings of a set of objects, has attracted much interest recently because of its numerous practical applications. While a wide variety of approaches including graph partitioning, maximum likelihood, genetic algorithms, and voting-merging have been proposed so far to solve this problem, virtually all of them work on hard partitionings, i.e., where an object is a member of exactly one cluster in any individual solution. However, many clustering algorithms such as fuzzy c-means naturally output soft partitionings of data, and forcibly hardening these partitions before applying a consensus method potentially involves loss of valuable information. In this article we propose several consensus algorithms that can be applied directly to soft clusterings. Experimental results over a variety of real-life datasets are also provided to show that using soft clusterings as input does offer significant advantages, especially when dealing with vertically partitioned data. 相似文献
75.
Amit Kumar Dubey Praveen Gupta Subashisa Dutta Bimlesh Kumar 《International journal of remote sensing》2013,34(23):7815-7827
In this study, river stage variation derived from satellite altimetry was used to assess the water level, monthly discharge, and annual water yield at six virtual gauging stations at the braided reaches of the Brahmaputra River. The braided reaches of the river dynamically change their planform, thalweg line, and aggradation or degradation period. Stage records derived from the Envisat satellite of the European Space Agency and Topex/Poseidon of NASA/CNES were used for the period 2002–2010. Spatial interpolation and datum correction were applied on altimetry-derived river stage records before analysis. A correlation and error analysis between the in situ and satellite-altimetry-derived stages was carried out for these stations for both monsoon and non-monsoon seasons. Yearly optical satellite images were used for qualitative assessment of temporal variations in aggradation/degradation phases at the gauging stations. Using the pseudo-rating curve, discharges at two virtual gauging stations were estimated. The results show that the altimetry-estimated discharges are of good agreement with observed discharge for the monsoon months (June–September) as compared with the non-monsoon months (October–May). In order to assess the annual water yield variability, yearly variation in annual water yield from the altimetry data was also estimated and compared to that observed. The estimated annual water yields were 90% accurate. Similarly, the long-term averaged monthly discharge series estimated from satellite altimetry closely follows the temporal trend of that of the observed series. 相似文献
76.
R. K. Dutta S. Paul A. B. Chattopadhyay 《The International Journal of Advanced Manufacturing Technology》2006,31(5-6):434-442
Face milling is a process predominantly affected by dynamic variation of cutting forces, thermo-mechanical shocks and vibration leading to catastrophic tool failure along with gradual wear of the inserts. Keeping in view the industrial importance of this process, it is necessary to devise suitable methods to predict in advance the onset of tool failure without grossly impairing the machining set-up and the job. Hence, the applicability of back propagation neural network with delta bar delta learning rule for faster convergence has been studied with the above objective. The multi sensor based tool condition monitoring strategy shows that the learning rate adaptation scheme combined with the selection of suitable process parameters drastically reduces the training time of the artificial neural network without dispensing with the prediction accuracy. 相似文献
77.
A novel image-based defect identification and coding technique has been proposed for fluted ingots, which are used for the production of locomotive wheels. The edge density map has been used for defect identification and an object-based coding approach has been applied for the storage of defective ingots. The complete scheme has been implemented in one of the integrated steel plants of India. 相似文献
78.
The net gain per unit length (G ) versus current (I ) is measured at various temperatures for 1.3 μm InGaAsP-InP double heterostructure lasers.G is found to vary linearly with the currentI at a given temperature. The gain bandwidth is found to decrease with decreasing temperature. The lasing photon energy decreases at 0.325 meV/K with increasing temperature. Also, the slopedG/dI at the lasing photon energies decreases with increasing temperature. This decrease is more rapid forT > sim210 K. This faster decrease is consistent with the observed higher temperature dependence of threshold (low T0 at high temperatures) of 1.3 μm InGaAsP lasers. A carrier loss mechanism, due to Auger recombination, also predicts thatdG/dI should decrease much faster with increasing temperature at high temperatures. We also find that the slopedG/dI decreases slowly with increasing temperature for a GaAs laser, which is consistent with the observed temperature dependence of threshold of these lasers. 相似文献
79.
Lipids and phytosterol oxidation products in commercial potato crisps commonly consumed in Sweden 总被引:1,自引:0,他引:1
Elham Tabee Margaretha Jägerstad Paresh C. Dutta 《European Food Research and Technology》2008,227(3):745-755
The stability of frying oils and fried foods is mainly affected by the fatty acids present and by the types and levels of
minor components such as phytosterols and tocopherols. This study assessed the current status of lipid composition and the
occurrence of oxidised phytosterols as a parameter of lipid oxidation in potato crisps available in the Swedish market. Fatty
acid composition and concentrations of tocopherols, sterols and phytosterol oxidation products (POPs) were determined in 16
commercial potato crisp samples of two types, distinguished by a high or low fat content. The fatty acid composition in most
samples was dominated by saturated and monounsaturated fatty acids. The sum of α-tocopherol and γ-tocopherol content varied
from undetectable levels to 10.2 mg/100 g potato crisps, with α-tocopherol dominating. Among the tocotrienols, α-tocotrienol
and γ-tocotrienol were present in almost equal proportions, while δ-tocotrienol was present in all samples but in smaller
amounts. Fatty acid composition, tocopherol and tocotrienol content, showed that all potato crisp samples were prepared in
palm oil or a blend of palm oil and unspecified fats and oils. Total sterol content ranged from 10.2 to 93.1 mg/100 g sample,
with β-sitosterol being the major sterol in all samples. The content of POPs ranged from 0.05 to 0.68 mg/100 g potato crisps.
In general, there were no significant differences in content of POPs between high and low fat samples, and generally no correlations
could be established between content of POPs and fatty acid, tocopherol, tocotrienol, and sterol content among the potato
crisp samples. 相似文献
80.
The starting point of our research is the following problem: given a doubling metric ?=(V,d), can one (efficiently) find an unweighted graph G′=(V′,E′) with V?V′ whose shortest-path metric d′ is still doubling, and which agrees with d on V×V? While it is simple to show that the answer to the above question is negative if distances must be preserved exactly. However, allowing a (1+ε) distortion between d and d′ enables us bypass this hurdle, and obtain an unweighted graph G′ with doubling dimension at most a factor O(log?ε ?1) times the doubling dimension of G.More generally, this paper gives algorithms that construct graphs G′ whose convex (or geodesic) closure has doubling dimension close to that of ?, and the shortest-path distances in G′ closely approximate those of ? when restricted to V×V. Similar results are shown when the metric ? is an additive (tree) metric and the graph G′ is restricted to be a tree. 相似文献