3,765 research outputs found
Decoding Single Molecule Time Traces with Dynamic Disorder
Single molecule time trajectories of biomolecules provide glimpses into
complex folding landscapes that are difficult to visualize using conventional
ensemble measurements. Recent experiments and theoretical analyses have
highlighted dynamic disorder in certain classes of biomolecules, whose dynamic
pattern of conformational transitions is affected by slower transition dynamics
of internal state hidden in a low dimensional projection. A systematic means to
analyze such data is, however, currently not well developed. Here we report a
new algorithm - Variational Bayes-double chain Markov model (VB-DCMM) - to
analyze single molecule time trajectories that display dynamic disorder. The
proposed analysis employing VB-DCMM allows us to detect the presence of dynamic
disorder, if any, in each trajectory, identify the number of internal states,
and estimate transition rates between the internal states as well as the rates
of conformational transition within each internal state. Applying VB-DCMM
algorithm to single molecule FRET data of H-DNA in 100 mM-Na solution,
followed by data clustering, we show that at least 6 kinetic paths linking 4
distinct internal states are required to correctly interpret the duplex-triplex
transitions of H-DNA
A STUDY ON THE FACTORS INFLUENCING THE INTENTION OF BLOG USAGE
Blogs are a new type of media that have recently become popular users on the World Wide Web and have influence throughout society. The purpose of this study is to examine social motivations influencing intention of blog usage. Based on Technology Acceptance Model and Motivation Theory, This study considered perceived usefulness, perceived ease of use, reputation, reciprocity, enjoyment of helping, social identity as the determinants of influencing the intention of blog usage. The purposed model was empirically evaluated using online survey data collected from 342 user of popular blog site in Korea (NAVER Blog , cyworld mihompy, daum blog, yahoo blog etc) The results revealed that perceived usefulness, perceived ease of use, reciprocity, social identity affected directly the intention of blog usage. Also social identity has moderate effect via reciprocity and enjoyment of helping on blog usage. This study contributes to a theoretical understanding of the factors as social motivation that affect the usage of blogs. Practically this study results provide blog service providers useful strategic insights and service guideline to enhance user\u27s intention of blogs
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Long-Term Monitoring and Analysis of a Curved Concrete Box-Girder Bridge
Capital investment in national infrastructure is significant. The need to maintain and protect critical infrastructure links has led in recent years to significant developments in the area of structural health monitoring. The objective is to track a structure’s long-term performance, typically using sensors, and to successively compare the most recently measured responses with prior response history. During construction of the West Street On-Ramp, a curved concrete box girder bridge, located in the city of Anaheim (California), eleven accelerometers were permanently installed on its bridge deck. The associated data acquisition system was configured to record once a specified threshold acceleration response was exceeded; during the period 2002–2010 a total of 1350 datasets including six earthquakes, for each of the eleven sensors, were acquired. This automatically acquired data was supplemented, during the summer of 2009, with responses measured during controlled vehicle tests. Six accelerometers were additionally installed on the frame of the weighed test vehicle. This paper presents the findings of the analyses of these measured data sets and serves to inform owners and managers as to the potential feedback from their instrumentation investment. All response histories were analyzed using frequency domain techniques for system identification. Extraction of the modal characteristics revealed a continuous reduction, of approximately 5%, in the first three natural frequencies over the period of the study. The measured responses from the vehicle sensors are discussed in the context of identifying the potential for bridge frequency measurement using instrumented vehicles
Mask Off: Analytic-based Malware Detection By Transfer Learning and Model Personalization
The vulnerability of smartphones to cyberattacks has been a severe concern to
users arising from the integrity of installed applications (\textit{apps}).
Although applications are to provide legitimate and diversified on-the-go
services, harmful and dangerous ones have also uncovered the feasible way to
penetrate smartphones for malicious behaviors. Thorough application analysis is
key to revealing malicious intent and providing more insights into the
application behavior for security risk assessments. Such in-depth analysis
motivates employing deep neural networks (DNNs) for a set of features and
patterns extracted from applications to facilitate detecting potentially
dangerous applications independently. This paper presents an Analytic-based
deep neural network, Android Malware detection (ADAM), that employs a
fine-grained set of features to train feature-specific DNNs to have consensus
on the application labels when their ground truth is unknown. In addition, ADAM
leverages the transfer learning technique to obtain its adjustability to new
applications across smartphones for recycling the pre-trained model(s) and
making them more adaptable by model personalization and federated learning
techniques. This adjustability is also assisted by federated learning guards,
which protect ADAM against poisoning attacks through model analysis. ADAM
relies on a diverse dataset containing more than 153000 applications with over
41000 extracted features for DNNs training. The ADAM's feature-specific DNNs,
on average, achieved more than 98% accuracy, resulting in an outstanding
performance against data manipulation attacks
Young wall realization of crystal graphs for U_q(C_n^{(1)})
We give a realization of crystal graphs for basic representations of the
quantum affine algebra U_q(C_n^{(1)}) using combinatorics of Young walls. The
notion of splitting blocks plays a crucial role in the construction of crystal
graphs
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Competition between B-Z and B-L transitions in a single DNA molecule: Computational studies
Under negative torsion, DNA adopts left-handed helical forms, such as Z-DNA and L-DNA. Using the random copolymer model developed for a wormlike chain, we represent a single DNA molecule with structural heterogeneity as a helical chain consisting of monomers which can be characterized by different helical senses and pitches. By Monte Carlo simulation, where we take into account bending and twist fluctuations explicitly, we study sequence dependence of B-Z transitions under torsional stress and tension focusing on the interaction with B-L transitions. We consider core sequences, (GC)(n) repeats or (TG)(n) repeats, which can interconvert between the right-handed B form and the left-handed Z form, imbedded in a random sequence, which can convert to left-handed L form with different (tension dependent) helical pitch. We show that Z-DNA formation from the (GC)(n) sequence is always supported by unwinding torsional stress but Z-DNA formation from the (TG)(n) sequence, which are more costly to convert but numerous, can be strongly influenced by the quenched disorder in the surrounding random sequence.National Research Foundation NRF-2012 R1A1A3013044 NRF-2014R1A1A2055681NRF-2012R1A1A2021736IBS-R023-D1NRF-2015R1A2A2A01005916Chemistr
Estimates of Discharge Coefficient in Levee Breach Under Two Different Approach Flow Types
The amount of released water (discharge) in a levee breach is a primary input variable to establish an emergency action plan for the area next to the levee. However, although several studies have been conducted, there is still no widely applicable discharge coefficient formula; this needs to be known to estimate discharge amount through an opening caused by a levee breach. Sometimes, the discharge coefficient developed for a sharp crested side weir is used to rate the discharge, but, in case of a levee breach, the resulting geometry and flow types are similar to that over a broad crested weir. Thus, in this study, two different openings—rectangular and trapezoidal shape—are constructed in the center of a levee at a height of 0.6m to replicate levee breach scenarios, and the effect of two different approach flow types—the river type approach and reservoir type approach—are explored to suggest a discharge coefficient formula applicable for discharge rating for a levee breach. The results show that the ratio of head above the bottom of an opening and the opening width is a key variable for calculating the discharge coefficient of a reservoir type, but the approach Froude number should also be considered for a river type approach. The measured data are used to improve rating equations and will be useful in the future to validate computational fluid dynamics simulations of wave propagation during levee failure into the inundation area
Testing the Electronic Throttle Control
In this report, we summarize our approach for testing the Electronic Throttle Control (ETC) system. We reformulate the ETC model based on the MATLAB/SIMULINK model provided by the Berkeley group. We specify the ETC model using the hybrid modeling language called CHARON. From the CHARON model, we generate test sequences based on the control-flow and data-flow criteria. These are transformed into test cases which may be used to test an implementation of the ETC system
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