399 research outputs found
Modulation of a quantized vortex street with a vibrating obstacle
Dynamics of a superfluid flow past an obstacle are investigated by solving
the Gross-Pitaevskii equation numerically. For an appropriate velocity and size
of the obstacle, quantized vortices are periodically generated in the wake,
which form a Benard-von Karman vortex street. It is found that vibration of an
obstacle modulates the vortex street breaking a symmetry.Comment: 6 pages, 5 figures, Proceedings of IUTAM Symposium 2012:
"Understanding Common Aspects of Extreme Events in Fluids"; Sec 3.2 extende
Relativistic mean-field model with density-dependent meson-nucleon couplings
Within the relativistic mean-field approach, we extend the Miyazaki model,
where the NN and NN interactions are modified to suppress the
couplings between positive- and negative-energy states of a nucleon in matter.
Assuming appropriate density-dependence of the meson-nucleon couplings, we
study nuclear matter and finite nuclei. The model can reproduce the observed
properties of O and Ca well. We also examine if the model is
natural.Comment: 6 pages, 3 figure
When remembering the past suppresses memory for future actions
Remembering planned actions at the correct time in the future is an integral component of prospective cognition. Recent studies on future remembering have led to suggestions that prospective cognition might be based on past experience. To test this hypothesis, we focused on retrieval-induced forgetting (RIF), which usually indicates that remembering past events suppresses memory for related but different past events. The current study assessed RIF in two kinds of event-based prospective memory (PM) tasks using either focal or non-focal cues for ongoing tasks. Participants studied six members from each of eight taxonomic categories and then practiced recalling three of the six members from four of the eight categories using category-stem cues. This retrieval practice suppressed the detection of non-practiced members of the practiced categories during the PM task with non-focal cues (Experiment 1) but not with focal cues (Experiment 2). The results suggest that recall of certain items inhibits the function of the others as PM cues, but only if the PM task does not largely share its processing with the ongoing task
Privacy-Preserving Hierarchical Anonymization Framework over Encrypted Data
Smart cities, which can monitor the real world and provide smart services in
a variety of fields, have improved people's living standards as urbanization
has accelerated. However, there are security and privacy concerns because smart
city applications collect large amounts of privacy-sensitive information from
people and their social circles. Anonymization, which generalizes data and
reduces data uniqueness is an important step in preserving the privacy of
sensitive information. However, anonymization methods frequently require large
datasets and rely on untrusted third parties to collect and manage data,
particularly in a cloud environment. In this case, private data leakage remains
a critical issue, discouraging users from sharing their data and impeding the
advancement of smart city services. This problem can be solved if the
computational entity can perform the anonymization process without obtaining
the original plain text. This study proposed a hierarchical k-anonymization
framework using homomorphic encryption and secret sharing composed of two types
of domains. Different computing methods are selected flexibly, and two domains
are connected hierarchically to obtain higher-level anonymization results in an
efficient manner. The experimental results show that connecting two domains can
accelerate the anonymization process, indicating that the proposed secure
hierarchical architecture is practical and efficient.Comment: 8 pages, 12 figures, submitted to IEEE TRANSACTIONS ON INDUSTRIAL
INFORMATICS and under revie
Software Defined Media: Virtualization of Audio-Visual Services
Internet-native audio-visual services are witnessing rapid development. Among
these services, object-based audio-visual services are gaining importance. In
2014, we established the Software Defined Media (SDM) consortium to target new
research areas and markets involving object-based digital media and
Internet-by-design audio-visual environments. In this paper, we introduce the
SDM architecture that virtualizes networked audio-visual services along with
the development of smart buildings and smart cities using Internet of Things
(IoT) devices and smart building facilities. Moreover, we design the SDM
architecture as a layered architecture to promote the development of innovative
applications on the basis of rapid advancements in software-defined networking
(SDN). Then, we implement a prototype system based on the architecture, present
the system at an exhibition, and provide it as an SDM API to application
developers at hackathons. Various types of applications are developed using the
API at these events. An evaluation of SDM API access shows that the prototype
SDM platform effectively provides 3D audio reproducibility and interactiveness
for SDM applications.Comment: IEEE International Conference on Communications (ICC2017), Paris,
France, 21-25 May 201
Role of Energy Offset in Nonradiative Voltage Loss in Organic Solar Cells
The voltage loss incurred by nonradiative charge recombination should be reduced to further improve the power conversion efficiency of organic solar cells (OSCs). This work discusses the nonradiative voltage loss in OSCs with systematically controlled energy offset between optical bandgap and charge transfer (CT) states. It is demonstrated that the nonradiative voltage loss is a function of the energy offset; it drops sharply with decreasing energy offset. By measuring the quantum yields of electroluminescence from OSCs and decay kinetics of CT states, it is found that the radiative decay rate of CT states becomes larger when the energy offset is negligible compared with those in conventional OSCs with sufficient energy offset. This behavior is rationalized by hybridization between CT and local excited states, resulting in a considerable enhancement of the oscillator strength of CT states. Based on a trend observed in this study, the precise mechanism by which the energy offset affects the nonradiative voltage loss is discussed
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