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171.
Aditya K. Ghose Pablo O. Hadjinian Abdul Sattar Jia-H. You Randy Goebel 《Computational Intelligence》2004,20(1):37-55
Most existing formalizations treat belief change as a single-step process, and ignore several problems that become important when a theory, or belief state, is revised over several steps. This paper identifies these problems, and argues for the need to retain all of the multiple possible outcomes of a belief change step, and for a framework in which the effects of a belief change step persist as long as is consistently possible. To demonstrate that such a formalization is indeed possible, we develop a framework, which uses the language of PJ-default logic (Delgrande and Jackson 1991) to represent a belief state, and which enables the effects of a belief change step to persist by propagating belief constraints . Belief change in this framework maps one belief state to another, where each belief state is a collection of theories given by the set of extensions of the PJ-default theory representing that belief state. Belief constraints do not need to be separately recorded; they are encoded as clearly identifiable components of a PJ-default theory. The framework meets the requirements for iterated belief change that we identify and satisfies most of the AGM postulates (Alchourrón, Gärdenfors, and Makinson 1985) as well. 相似文献
172.
Aditya M. VORA 《Frontiers of Materials Science in China》2008,2(3):311-315
In the present article, the theoretical calculations of the phonon dispersion curves (PDCs) of five alkali metals viz. Li,
Na, K, Rb, Cs and their four equiatomic sodium-based binary alloys viz. Na0.5Li0.5, Na0.5K0.5, Na0.5Rb0.5 and Na0.5Cs0.5 to second order in a local model potential is discussed in terms of the realspace sum of the Born von Karman central force
constants. Instead of the concentration average of the force constants of pure alkali metals, the pseudo-alloy-atom (PAA)
is adopted to directly compute the force constants of the four equiatomic sodium based binary alloys and was successfully
applied. The exchange and correlation functions due to the Hartree (H) and Ichimaru-Utsumi (IU) are used to investigate the
influence of the screening effects. The phonon frequencies of alkali metals and their four equiatomic sodium-based binary
alloys in the longitudinal branch are more sensitive to the exchange and correlation effects in comparison with the transverse
branches. The PDCs of pure alkali metals are found in qualitative agreement with the available experimental data. The frequencies
in the longitudinal branch are suppressed rather due to IU-screening function than those due to static H-screening function. 相似文献
173.
The field-dependent photocurrent spectrum of individual carbon nanotubes is measured using a displacement photocurrent technique. A series of peaks is observed in the photocurrent corresponding to both excitonic and free carrier transitions. The photocurrent peak corresponding to the ground state exciton increases by a factor of 200 beyond a critical electric field, and shows both red and blue shifts depending on the field regime. This provides evidence for field-induced mixing between excitonic and free carrier states. 相似文献
174.
Riccardo Di Pietro Iyad Nasrallah Joshua Carpenter Eliot Gann Lisa Sophie Kölln Lars Thomsen Deepak Venkateshvaran Kathryn O'Hara Aditya Sadhanala Michael Chabinyc Christopher R. McNeill Antonio Facchetti Harald Ade Henning Sirringhaus Dieter Neher 《Advanced functional materials》2016,26(44):8011-8022
Polymer semiconductors provide unique possibilities and flexibility in tailoring their optoelectronic properties to match specific application demands. The recent development of semicrystalline polymers with strongly improved charge transport properties forces a review of the current understanding of the charge transport mechanisms and how they relate to the polymer's chemical and structural properties. Here, the charge density dependence of field effect mobility in semicrystalline polymer semiconductors is studied. A simultaneous increase in mobility and its charge density dependence, directly correlated to the increase in average crystallite size of the polymer film, is observed. Further evidence from charge accumulation spectroscopy shows that charges accumulate in the crystalline regions of the polymer film and that the increase in crystallite size affects the average electronic orbitals delocalization. These results clearly point to an effect that is not caused by energetic disorder. It is instead shown that the inclusion of short range coulomb repulsion between charge carriers on nanoscale crystalline domains allows describing the observed mobility dependence in agreement with the structural and optical characterization. The conclusions that are extracted extend beyond pure transistor characterization and can provide new insights into charge carrier transport for regimes and timescales that are relevant to other optoelectronic devices. 相似文献
175.
Ning G Shum P Aditya S Gong Y 《Journal of the Optical Society of America. A, Optics, image science, and vision》2007,24(1):188-191
We propose a continuously tunable, dual free spectral range (FSR) photonic microwave notch filter configuration using a high-birefringence linearly chirped fiber Bragg grating (Hi-Bi LCFBG) that is connected in a Sagnac loop using a Hi-Bi coupler. The configuration employs double sideband modulation and can generate two FSRs simultaneously. The larger FSR corresponds to the differential time delay of the Hi-Bi LCFBG and the Hi-Bi pigtails of the coupler; the smaller FSR corresponds to the time delay between the arms of the Sagnac loop. Measured results demonstrate dual FSR, a large notch rejection, and that the FSR is easily tunable by tuning the LCFBG. We also present the filter transfer function for the design. Experimental results agree well with the theoretical analysis. 相似文献
176.
A novel design of a microwave photonic filter with infinite impulse response is demonstrated. The design is based on a dual drive modulator with an optoelectronic feedback loop. The stopband of the filter can be switched to passband and vice versa by switching the bias point of the dual drive modulator. Measured results confirm the theoretical expressions and demonstrate a rejection ratio and frequency selectivity which is greater than 30 dB. 相似文献
177.
178.
This article documents an action-research and collaborative-design process for building a disaster-prepared public space and water infrastructure in Thecho, Nepal. When the 2015 Gorkha earthquake devastated the country, public open spaces provided safety and resources post-disaster. The project identifies the paati, an existing public space typology, as the genius loci and embeds the paatis with new public infrastructure. Combining earthquake reconstruction, historical preservation, and risk reduction, the intervention provides improved daily water access and a safe space to gather post-disaster. Documenting and reflecting on this process illustrates the importance of ethnographic fieldwork and local partnerships in designing for a disaster-prepared public realm. 相似文献
179.
Gaurav Sant Aditya Kumar Cedric Patapy Gwenn Le Saout Karen Scrivener 《Cement and Concrete Research》2012,42(11):1447-1455
This research investigates the influence of alkali hydroxides on unrestrained volume changes. A detailed multi-method approach is used to characterize the progress of cement hydration, autogenous and drying volume changes (i.e., shrinkage), autogenous RH decrease, compressive strength development, solid and liquid phases and the pore structure. It is noted that under autogenous conditions, alkalis magnify shrinkage; while upon external drying the extent of shrinkage is more similar. This is contrary to expectations which suggest that the reduction in the water activity and the negative pressure developed in the liquid phase, produced by alkali enrichment, should reduce shrinkage. Analysis of the autogenous RH decrease, pore solution chemistry and the mechanical properties indicates that the bulk shrinkage response is linked to multiple parameters including: (1) increased self-desiccation at early ages, (2) a reduction in the strength (and stiffness) of alkali-enriched systems and (3) liquid saturation effects. 相似文献
180.
Abhrajit Ghosh Yitzchak M. Gottlieb Aditya Naidu Akshay Vashist Alexander Poylisher Ayumu Kubota Yukiko Sawaya Akira Yamada 《中国通信》2013,10(3):56-66
In this paper, we present Real-Time Flow Filter (RTFF) —a system that adopts a middle ground between coarse-grained volume anomaly detection and deep packet in-spection. RTFF was designed with the goal of scaling to high volume data feeds that are common in large Tier-1 ISP networks and providing rich, timely information on ob-served attacks. It is a software solution that is designed to run on off-the-shelf hardware platforms and incorporates a scalable data processing architecture along with lightweight analysis algorithms that make it suitable for deployment in large networks. RTFF also makes use of state of the art machine learning algorithms to construct attack models that can be used to detect as well as predict attacks. 相似文献