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Value clashes, power competition and community trust: why an NGO's earthquake recovery program faltered in rural China
Probabilistic Label Relation Graphs with Ising Models
We consider classification problems in which the label space has structure. A
common example is hierarchical label spaces, corresponding to the case where
one label subsumes another (e.g., animal subsumes dog). But labels can also be
mutually exclusive (e.g., dog vs cat) or unrelated (e.g., furry, carnivore). To
jointly model hierarchy and exclusion relations, the notion of a HEX (hierarchy
and exclusion) graph was introduced in [7]. This combined a conditional random
field (CRF) with a deep neural network (DNN), resulting in state of the art
results when applied to visual object classification problems where the
training labels were drawn from different levels of the ImageNet hierarchy
(e.g., an image might be labeled with the basic level category "dog", rather
than the more specific label "husky"). In this paper, we extend the HEX model
to allow for soft or probabilistic relations between labels, which is useful
when there is uncertainty about the relationship between two labels (e.g., an
antelope is "sort of" furry, but not to the same degree as a grizzly bear). We
call our new model pHEX, for probabilistic HEX. We show that the pHEX graph can
be converted to an Ising model, which allows us to use existing off-the-shelf
inference methods (in contrast to the HEX method, which needed specialized
inference algorithms). Experimental results show significant improvements in a
number of large-scale visual object classification tasks, outperforming the
previous HEX model.Comment: International Conference on Computer Vision (2015
Pairing Correlations Near a Kondo-Destruction Quantum Critical Point
Motivated by the unconventional superconductivity observed in heavy-fermion
metals, we investigate pairing susceptibilities near a continuous quantum phase
transition of the Kondo-destruction type. We solve two-impurity Bose-Fermi
Anderson models with Ising and Heisenberg forms of the interimpurity exchange
interaction using continuous-time quantum Monte-Carlo and numerical
renormalization-group methods. Each model exhibits a Kondo-destruction quantum
critical point separating Kondo-screened and local-moment phases. For
antiferromagnetic interimpurity exchange interactions, singlet pairing is found
to be enhanced in the vicinity of the transition. Implications of this result
for heavy-fermion superconductivity are discussed.Comment: 5 pages, 5 figures + supplementary material 2 page, 2 figures:
Replaced with published versio
Optimizing NOTEARS Objectives via Topological Swaps
Recently, an intriguing class of non-convex optimization problems has emerged
in the context of learning directed acyclic graphs (DAGs). These problems
involve minimizing a given loss or score function, subject to a non-convex
continuous constraint that penalizes the presence of cycles in a graph. In this
work, we delve into the optimization challenges associated with this class of
non-convex programs. To address these challenges, we propose a bi-level
algorithm that leverages the non-convex constraint in a novel way. The outer
level of the algorithm optimizes over topological orders by iteratively
swapping pairs of nodes within the topological order of a DAG. A key innovation
of our approach is the development of an effective method for generating a set
of candidate swapping pairs for each iteration. At the inner level, given a
topological order, we utilize off-the-shelf solvers that can handle linear
constraints. The key advantage of our proposed algorithm is that it is
guaranteed to find a local minimum or a KKT point under weaker conditions
compared to previous work and finds solutions with lower scores. Extensive
experiments demonstrate that our method outperforms state-of-the-art approaches
in terms of achieving a better score. Additionally, our method can also be used
as a post-processing algorithm to significantly improve the score of other
algorithms. Code implementing the proposed method is available at
https://github.com/duntrain/topo.Comment: 39 pages, 12 figures, ICML 202
Mouse cytoplasmic dynein intermediate chains: identification of new isoforms, alternative splicing and tissue distribution of transcripts
BACKGROUND: Intracellular transport of cargoes including organelles, vesicles, signalling molecules, protein complexes, and RNAs, is essential for normal function of eukaryotic cells. The cytoplasmic dynein complex is an important motor that moves cargos along microtubule tracks within the cell. In mammals this multiprotein complex includes dynein intermediate chains 1 and 2 which are encoded by two genes, Dync1i1 and Dync1i2. These proteins are involved in dynein cargo binding and dynein complexes with different intermediate chains bind to specific cargoes, although the mechanisms to achieve this are not known. The DYNC1I1 and DYNC1I2 proteins are translated from different splice isoforms, and specific forms of each protein are essential for the function of different dynein complexes in neurons. METHODOLOGY/PRINCIPAL FINDINGS: Here we have undertaken a systematic survey of the dynein intermediate chain splice isoforms in mouse, basing our study on mRNA expression patterns in a range of tissues, and on bioinformatics analysis of mouse, rat and human genomic and cDNA sequences. We found a complex pattern of alternative splicing of both dynein intermediate chain genes, with maximum complexity in the embryonic and adult nervous system. We have found novel transcripts, including some with orthologues in human and rat, and a new promoter and alternative non-coding exon 1 for Dync1i2. CONCLUSIONS/SIGNIFICANCE: These data, including the cloned isoforms will be essential for understanding the role of intermediate chains in the cytoplasmic dynein complex, particularly their role in cargo binding within individual tissues including different brain regions
Cross-subject dual-domain fusion network with task-related and task-discriminant component analysis enhancing one-shot SSVEP classification
This study addresses the significant challenge of developing efficient
decoding algorithms for classifying steady-state visual evoked potentials
(SSVEPs) in scenarios characterized by extreme scarcity of calibration data,
where only one calibration is available for each stimulus target. To tackle
this problem, we introduce a novel cross-subject dual-domain fusion network
(CSDuDoFN) incorporating task-related and task-discriminant component analysis
(TRCA and TDCA) for one-shot SSVEP classification. The CSDuDoFN framework is
designed to comprehensively transfer information from source subjects, while
TRCA and TDCA are employed to exploit the single available calibration of the
target subject. Specifically, we develop multi-reference least-squares
transformation (MLST) to map data from both source subjects and the target
subject into the domain of sine-cosine templates, thereby mitigating
inter-individual variability and benefiting transfer learning. Subsequently,
the transformed data in the sine-cosine templates domain and the original
domain data are separately utilized to train a convolutional neural network
(CNN) model, with the adequate fusion of their feature maps occurring at
distinct network layers. To further capitalize on the calibration of the target
subject, source aliasing matrix estimation (SAME) data augmentation is
incorporated into the training process of the ensemble TRCA (eTRCA) and TDCA
models. Ultimately, the outputs of the CSDuDoFN, eTRCA, and TDCA are combined
for SSVEP classification. The effectiveness of our proposed approach is
comprehensively evaluated on three publicly available SSVEP datasets, achieving
the best performance on two datasets and competitive performance on one. This
underscores the potential for integrating brain-computer interface (BCI) into
daily life.Comment: 10 pages,6 figures, and 3 table
The bioinformatics resource for oral pathogens
Complete genomic sequences of several oral pathogens have been deciphered and multiple sources of independently annotated data are available for the same genomes. Different gene identification schemes and functional annotation methods used in these databases present a challenge for cross-referencing and the efficient use of the data. The Bioinformatics Resource for Oral Pathogens (BROP) aims to integrate bioinformatics data from multiple sources for easy comparison, analysis and data-mining through specially designed software interfaces. Currently, databases and tools provided by BROP include: (i) a graphical genome viewer (Genome Viewer) that allows side-by-side visual comparison of independently annotated datasets for the same genome; (ii) a pipeline of automatic data-mining algorithms to keep the genome annotation always up-to-date; (iii) comparative genomic tools such as Genome-wide ORF Alignment (GOAL); and (iv) the Oral Pathogen Microarray Database. BROP can also handle unfinished genomic sequences and provides secure yet flexible control over data access. The concept of providing an integrated source of genomic data, as well as the data-mining model used in BROP can be applied to other organisms. BROP can be publicly accessed at
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