1,259 research outputs found
Electric field thermopower modulation analyses of the operation mechanism of transparent amorphous SnO thin-film transistor
Transparent amorphous oxide semiconductors (TAOSs) based transparent
thin-film transistors (TTFTs) with high field effect mobility are essential for
developing advanced flat panel displays. Among TAOSs, amorphous (a-) SnO
has several advantages against current a-InGaZnO4 such as higher field effect
mobility and being indium free. Although a-SnO TTFT has been demonstrated
several times, the operation mechanism has not been clarified thus far due to
the strong gas sensing characteristics of SnO. Here we clarify the
operation mechanism of a-SnO TTFT by electric field thermopower modulation
analyses. We prepared a bottom-gate top-contact type TTFT using 4.2-nm-thick
a-SnO as the channel without any surface passivation. The effective
thickness of the conducting channel was ~1.7 + - 0.4 nm in air and in vacuum,
but a large threshold gate voltage shift occurred in different atmospheres;
this is attributed to carrier depletion near at the top surface (~2.5 nm) of
the a-SnO due to its interaction with the gas molecules and the resulting
shift in the Fermi energy. The present results would provide a fundamental
design concept to develop a-SnO TTFT
SpreadCluster: Recovering Versioned Spreadsheets through Similarity-Based Clustering
Version information plays an important role in spreadsheet understanding,
maintaining and quality improving. However, end users rarely use version
control tools to document spreadsheet version information. Thus, the
spreadsheet version information is missing, and different versions of a
spreadsheet coexist as individual and similar spreadsheets. Existing approaches
try to recover spreadsheet version information through clustering these similar
spreadsheets based on spreadsheet filenames or related email conversation.
However, the applicability and accuracy of existing clustering approaches are
limited due to the necessary information (e.g., filenames and email
conversation) is usually missing. We inspected the versioned spreadsheets in
VEnron, which is extracted from the Enron Corporation. In VEnron, the different
versions of a spreadsheet are clustered into an evolution group. We observed
that the versioned spreadsheets in each evolution group exhibit certain common
features (e.g., similar table headers and worksheet names). Based on this
observation, we proposed an automatic clustering algorithm, SpreadCluster.
SpreadCluster learns the criteria of features from the versioned spreadsheets
in VEnron, and then automatically clusters spreadsheets with the similar
features into the same evolution group. We applied SpreadCluster on all
spreadsheets in the Enron corpus. The evaluation result shows that
SpreadCluster could cluster spreadsheets with higher precision and recall rate
than the filename-based approach used by VEnron. Based on the clustering result
by SpreadCluster, we further created a new versioned spreadsheet corpus
VEnron2, which is much bigger than VEnron. We also applied SpreadCluster on the
other two spreadsheet corpora FUSE and EUSES. The results show that
SpreadCluster can cluster the versioned spreadsheets in these two corpora with
high precision.Comment: 12 pages, MSR 201
New methods to measure residues coevolution in proteins
<p>Abstract</p> <p>Background</p> <p>The covariation of two sites in a protein is often used as the degree of their coevolution. To quantify the covariation many methods have been developed and most of them are based on residues position-specific frequencies by using the mutual information (MI) model.</p> <p>Results</p> <p>In the paper, we proposed several new measures to incorporate new biological constraints in quantifying the covariation. The first measure is the mutual information with the amino acid background distribution (MIB), which incorporates the amino acid background distribution into the marginal distribution of the MI model. The modification is made to remove the effect of amino acid evolutionary pressure in measuring covariation. The second measure is the mutual information of residues physicochemical properties (MIP), which is used to measure the covariation of physicochemical properties of two sites. The third measure called MIBP is proposed by applying residues physicochemical properties into the MIB model. Moreover, scores of our new measures are applied to a robust indicator <it>conn(k) </it>in finding the covariation signal of each site.</p> <p>Conclusions</p> <p>We find that incorporating amino acid background distribution is effective in removing the effect of evolutionary pressure of amino acids. Thus the MIB measure describes more biological background information for the coevolution of residues. Besides, our analysis also reveals that the covariation of physicochemical properties is a new aspect of coevolution information.</p
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