121 research outputs found
Tag-based annotation creates better avatars
Avatar creation from human images allows users to customize their digital
figures in different styles. Existing rendering systems like Bitmoji,
MetaHuman, and Google Cartoonset provide expressive rendering systems that
serve as excellent design tools for users. However, twenty-plus parameters,
some including hundreds of options, must be tuned to achieve ideal results.
Thus it is challenging for users to create the perfect avatar. A machine
learning model could be trained to predict avatars from images, however the
annotators who label pairwise training data have the same difficulty as users,
causing high label noise. In addition, each new rendering system or version
update requires thousands of new training pairs. In this paper, we propose a
Tag-based annotation method for avatar creation. Compared to direct annotation
of labels, the proposed method: produces higher annotator agreements, causes
machine learning to generates more consistent predictions, and only requires a
marginal cost to add new rendering systems.Comment: 15 pages, 7 figures, 4 table
Energy-efficient Connected Cruise Control with Lean Penetration of Connected Vehicles
This paper focuses on energy-efficient longitudinal controller design for a
connected automated truck that travels in mixed traffic consisting of connected
and non-connected vehicles. The truck has access to information about connected
vehicles beyond line of sight using vehicle-to-vehicle (V2V) communication. A
novel connected cruise control design is proposed which incorporates additional
delays into the control law when responding to distant connected vehicles to
account for the finite propagation of traffic waves. The speeds of
non-connected vehicles are modeled as stochastic processes. A fundamental
theorem is proven which links the spectral properties of the motion signals to
the average energy consumption. This enables us to tune controller parameters
and maximize energy efficiency. Simulations with synthetic data and real
traffic data are used to demonstrate the energy efficiency of the control
design. It is demonstrated that even with lean penetration of connected
vehicles, our controller can bring significant energy savings.Comment: This is submitted to IEEE Transactions on Intelligent Transportation
System
Energy-efficient Reactive and Predictive Connected Cruise Control
In this paper, we propose a framework for the longitudinal control of
connected and automated vehicles traveling in mixed traffic consisting of
connected and non-connected human-driven vehicles. Reactive and predictive
controllers are proposed. Reactive controllers are given by explicit feedback
control laws. In predictive controllers, the control input is optimized in a
receding-horizon fashion, which depends on the predictions of motions of
preceding vehicles. Beyond-line-of-sight information is obtained via
vehicle-to-vehicle (V2V) communication, and is utilized in the proposed
reactive and predictive controllers. Simulations utilizing real traffic data
are used to show that connectivity can bring significant energy savings.Comment: 18 pages, 12 figures, submitted to Transportation Research Part C:
Emerging Technologie
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Hybrid Li-Ion and Li-O-2 Battery Enabled by Oxyhalogen-Sulfur Electrochemistry
An All-Silicon Passive Optical Diode
A passive optical diode effect would be useful for on-chip optical information processing but has been difficult to achieve. Using a method based on optical nonlinearity, we demonstrate a forward-backward transmission ratio of up to 28 decibels within telecommunication wavelengths. Our device, which uses two silicon rings 5 micrometers in radius, is passive yet maintains optical nonreciprocity for a broad range of input power levels, and it performs equally well even if the backward input power is higher than the forward input. The silicon optical diode is ultracompact and is compatible with current complementary metal-oxide semiconductor processing
Top-gated graphene field-effect-transistors formed by decomposition of SiC
Top-gated, few-layer graphene field-effect transistors (FETs) fabricated on
thermally-decomposed semi-insulating 4H-SiC substrates are demonstrated.
Physical vapor deposited SiO2 is used as the gate dielectric. A two-dimensional
hexagonal arrangement of carbon atoms with the correct lattice vectors,
observed by high-resolution scanning tunneling microscopy, confirms the
formation of multiple graphene layers on top of the SiC substrates. The
observation of n-type and p-type transition further verifies Dirac Fermions
unique transport properties in graphene layers. The measured electron and hole
mobility on these fabricated graphene FETs are as high as 5400 cm2/Vs and 4400
cm2/Vs respectively, which are much larger than the corresponding values from
conventional SiC or silicon
Unveiling the Stable Nature of the Solid Electrolyte Interphase between Lithium Metal and LiPON via Cryogenic Electron Microscopy
The solid electrolyte interphase (SEI) is regarded as the most complex but
the least understood constituent in secondary batteries using liquid and solid
electrolytes. The nanostructures of SEIs were recently reported to be equally
important to the chemistry of SEIs for stabilizing Li metal in liquid
electrolyte. However, the dearth of such knowledge in all-solid-state battery
(ASSB) has hindered a complete understanding of how certain solid-state
electrolytes, such as LiPON, manifest exemplary stability against Li metal.
Characterizing such solid-solid interfaces is difficult due to the buried,
highly reactive, and beam-sensitive nature of the constituents within. By
employing cryogenic electron microscopy (cryo-EM), the interphase between Li
metal and LiPON is successfully preserved and probed, revealing a multilayer
mosaic SEI structure with concentration gradients of nitrogen and phosphorous,
materializing as crystallites within an amorphous matrix. This unique SEI
nanostructure is less than 80 nm and is shown stable and free of any organic
lithium containing species or lithium fluoride components, in contrast to SEIs
often found in state-of-the-art organic liquid electrolytes. Our findings
reveal insights on the nanostructures and chemistry of such SEIs as a key
component in lithium metal batteries to stabilize Li metal anode
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