2,567 research outputs found
A General Framework for Complex Network Applications
Complex network theory has been applied to solving practical problems from
different domains. In this paper, we present a general framework for complex
network applications. The keys of a successful application are a thorough
understanding of the real system and a correct mapping of complex network
theory to practical problems in the system. Despite of certain limitations
discussed in this paper, complex network theory provides a foundation on which
to develop powerful tools in analyzing and optimizing large interconnected
systems.Comment: 8 page
Dynamic MLP for MRI Reconstruction
As convolutional neural networks (CNN) become the most successful
reconstruction technique for accelerated Magnetic Resonance Imaging (MRI), CNN
reaches its limit on image quality especially in sharpness. Further improvement
on image quality often comes at massive computational costs, hindering their
practicability in the clinic setting. MRI reconstruction is essentially a
deconvolution problem, which demands long-distance information that is
difficult to be captured by CNNs with small convolution kernels. The
multi-layer perceptron (MLP) is able to model such long-distance information,
but it restricts a fixed input size while the reconstruction of images in
flexible resolutions is required in the clinic setting. In this paper, we
proposed a hybrid CNN and MLP reconstruction strategy, featured by dynamic MLP
(dMLP) that accepts arbitrary image sizes. Experiments were conducted using 3D
multi-coil MRI. Our results suggested the proposed dMLP can improve image
sharpness compared to its pure CNN counterpart, while costing minor additional
GPU memory and computation time. We further compared the proposed dMLP with
CNNs using large kernels and studied pure MLP-based reconstruction using a
stack of 1D dMLPs, as well as its CNN counterpart using only 1D convolutions.
We observed the enlarged receptive field has noticeably improved image quality,
while simply using CNN with a large kernel leads to difficulties in training.
Noticeably, the pure MLP-based method has been outperformed by CNN-involved
methods, which matches the observations in other computer vision tasks for
natural images
D-Unet: A Dual-encoder U-Net for Image Splicing Forgery Detection and Localization
Recently, many detection methods based on convolutional neural networks
(CNNs) have been proposed for image splicing forgery detection. Most of these
detection methods focus on the local patches or local objects. In fact, image
splicing forgery detection is a global binary classification task that
distinguishes the tampered and non-tampered regions by image fingerprints.
However, some specific image contents are hardly retained by CNN-based
detection networks, but if included, would improve the detection accuracy of
the networks. To resolve these issues, we propose a novel network called
dual-encoder U-Net (D-Unet) for image splicing forgery detection, which employs
an unfixed encoder and a fixed encoder. The unfixed encoder autonomously learns
the image fingerprints that differentiate between the tampered and non-tampered
regions, whereas the fixed encoder intentionally provides the direction
information that assists the learning and detection of the network. This
dual-encoder is followed by a spatial pyramid global-feature extraction module
that expands the global insight of D-Unet for classifying the tampered and
non-tampered regions more accurately. In an experimental comparison study of
D-Unet and state-of-the-art methods, D-Unet outperformed the other methods in
image-level and pixel-level detection, without requiring pre-training or
training on a large number of forgery images. Moreover, it was stably robust to
different attacks.Comment: 13 pages, 13 figure
Monazite behaviour during isothermal decompression in pelitic granulites: a case study from Dinggye, Tibetan Himalaya
Monazite is a key accessory mineral for metamorphic geochronology, but interpretation of its complex chemical and age zoning acquired during high-temperature metamorphism and anatexis remains a challenge. We investigate the petrology, pressureātemperature and timing of metamorphism in pelitic and psammitic granulites that contain monazite from the Greater Himalayan Crystalline Complex (GHC) in Dinggye, southern Tibet. These rocks underwent isothermal decompression from pressure of >10 kbar to ~5 kbar at temperatures of 750ā830 Ā°C, and recorded three metamorphic stages at kyanite (M1), sillimanite (M2) and cordierite-spinel grade (M3). Monazite and zircon crystals were dated by microbeam techniques either as grain separates or in thin sections. UāThāPb ages are linked to specific conditions of mineral growth on the basis of zoning patterns, trace element signatures, index mineral inclusions (melt inclusions, sillimanite and K-feldspar) in dated domains and textural relationships with co-existing minerals. The results show that inherited domains (500ā400 Ma) are preserved in monazite even at granulite-facies conditions. Few monazites or zircon yield ages related to the M1- stage (~30ā29 Ma), possibly corresponding to prograde melting by muscovite dehydration. During the early stage of isothermal decompression, inherited or prograde monazites in most samples were dissolved in the melt produced by biotite dehydration-melting. Most monazite grains crystallized from melt toward the end of decompression (M3-stage, 21ā19 Ma) and are chemically related to garnet breakdown reactions. Another peak of monazite growth occurred at final melt crystallization (~15 Ma), and these monazite grains are unzoned and are homogeneous in composition. In a regional context, our pressureātemperatureātime data constrains peak high-pressure metamorphism within the GHC to ~30ā29 Ma in Dinggye Himalaya. Our results are in line with a meltassisted exhumation of the GHC rocks
Quantum theory of light diffraction
At present, the theory of light diffraction only has the simple wave-optical
approach. In this paper, we study light diffraction with the approach of
relativistic quantum theory. We find that the slit length, slit width, slit
thickness and wave-length of light have affected to the diffraction intensity
and form of diffraction pattern. However, the effect of slit thickness on the
diffraction pattern can not be explained by wave-optical approach, and it can
be explained in quantum theory. We compare the theoretical results with single
and multiple slits experiment data, and find the theoretical results are
accordance with the experiment data. Otherwise, we give some theory prediction.
We think all the new prediction will be tested by the light diffraction
experiment.Comment: 10 page
Beyond ChatBots: ExploreLLM for Structured Thoughts and Personalized Model Responses
Large language model (LLM) powered chatbots are primarily text-based today,
and impose a large interactional cognitive load, especially for exploratory or
sensemaking tasks such as planning a trip or learning about a new city. Because
the interaction is textual, users have little scaffolding in the way of
structure, informational "scent", or ability to specify high-level preferences
or goals. We introduce ExploreLLM that allows users to structure thoughts, help
explore different options, navigate through the choices and recommendations,
and to more easily steer models to generate more personalized responses. We
conduct a user study and show that users find it helpful to use ExploreLLM for
exploratory or planning tasks, because it provides a useful schema-like
structure to the task, and guides users in planning. The study also suggests
that users can more easily personalize responses with high-level preferences
with ExploreLLM. Together, ExploreLLM points to a future where users interact
with LLMs beyond the form of chatbots, and instead designed to support complex
user tasks with a tighter integration between natural language and graphical
user interfaces.Comment: 19 pages, 11 figure
Bridging the Granularity Gap for Acoustic Modeling
While Transformer has become the de-facto standard for speech, modeling upon
the fine-grained frame-level features remains an open challenge of capturing
long-distance dependencies and distributing the attention weights. We propose
\textit{Progressive Down-Sampling} (PDS) which gradually compresses the
acoustic features into coarser-grained units containing more complete semantic
information, like text-level representation. In addition, we develop a
representation fusion method to alleviate information loss that occurs
inevitably during high compression. In this way, we compress the acoustic
features into 1/32 of the initial length while achieving better or comparable
performances on the speech recognition task. And as a bonus, it yields
inference speedups ranging from 1.20 to 1.47. By reducing the
modeling burden, we also achieve competitive results when training on the more
challenging speech translation task.Comment: ACL 2023 Finding
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