288 research outputs found
A role for SUMO modification in transcriptional repression and activation
Since the discovery of the SUMO (small ubiquitin-like modifier) family of proteins just over a decade ago, a plethora of substrates have been uncovered including many regulators of transcription. Conjugation of SUMO to target proteins has generally been considered as a repressive modification. However, there are now a growing number of examples where sumoylation has been shown to activate transcription. Here we discuss whether there is something intrinsically repressive about sumoylation, or if the outcome of this modification in the context of transcription will prove to be largely substrate-dependent. We highlight some of the technical challenges that will be faced by attempting to answer this question
Thermohydrodynamics in Quantum Hall Systems
A theory of thermohydrodynamics in two-dimensional electron systems in
quantizing magnetic fields is developed including a nonlinear transport regime.
Spatio-temporal variations of the electron temperature and the chemical
potential in the local equilibrium are described by the equations of
conservation with the number and thermal-energy flux densities. A model of
these flux densities due to hopping and drift processes is introduced for a
random potential varying slowly compared to both the magnetic length and the
phase coherence length. The flux measured in the standard transport experiment
is derived and is used to define a transport component of the flux density. The
equations of conservation can be written in terms of the transport component
only. As an illustration, the theory is applied to the Ettingshausen effect, in
which a one-dimensional spatial variation of the electron temperature is
produced perpendicular to the current.Comment: 10 pages, 1 figur
Image Enlargement Based on Proportional Salient Feature
This paper proposes an image enlargement methodthat produces proportional salient content of imagemagnification. To obtain the proportional salient image content:first, we enlarge the source image to the high size of the targetimage using uniform enlarging. Second, we slice the image intosections from top to bottom following the minimum energy anddetect the salient feature of the image. Third, we enlarge the sliceof the image region that does not containthe salient feature of theimage to the full size of the target image. The proposed methodhas been tested in several images, such as akiyo, butterfly,cameraman, canoe, dolphin, and parrot. The experimentalresults show that the proposed method results in a proportionalcontent for image enlargement in the different ratios comparedwith the comparison method
Robotic Wireless Sensor Networks
In this chapter, we present a literature survey of an emerging, cutting-edge,
and multi-disciplinary field of research at the intersection of Robotics and
Wireless Sensor Networks (WSN) which we refer to as Robotic Wireless Sensor
Networks (RWSN). We define a RWSN as an autonomous networked multi-robot system
that aims to achieve certain sensing goals while meeting and maintaining
certain communication performance requirements, through cooperative control,
learning and adaptation. While both of the component areas, i.e., Robotics and
WSN, are very well-known and well-explored, there exist a whole set of new
opportunities and research directions at the intersection of these two fields
which are relatively or even completely unexplored. One such example would be
the use of a set of robotic routers to set up a temporary communication path
between a sender and a receiver that uses the controlled mobility to the
advantage of packet routing. We find that there exist only a limited number of
articles to be directly categorized as RWSN related works whereas there exist a
range of articles in the robotics and the WSN literature that are also relevant
to this new field of research. To connect the dots, we first identify the core
problems and research trends related to RWSN such as connectivity,
localization, routing, and robust flow of information. Next, we classify the
existing research on RWSN as well as the relevant state-of-the-arts from
robotics and WSN community according to the problems and trends identified in
the first step. Lastly, we analyze what is missing in the existing literature,
and identify topics that require more research attention in the future
Traffic Light Signal Parameters Optimization using Modification of Multielement Genetic Algorithm
A strategy to optimize traffic light signal parameters is presented for solving traffic congestion problem using modification of the Multielement Genetic Algorithm (MEGA). The aim of this method is to improve the lack of vehicle throughput (FF ) of the works called as traffic light signal parameters optimization using the MEGA and Particle Swarm Optimization (PSO). In this case, the modification of MEGA is done by adding Hash-Table for saving some best populations for accelerating the recombination process of MEGA which is shortly called as H-MEGA. The experimental results show that the H-MEGA based optimization provides better performance than MEGA and PSO based methods (improving the FF of both MEGA and PSO based optimization methods by about 10.01% (from 82,63% to 92.64%) and 6.88% (from 85.76% to 92.64%), respectively). In addition, the H-MEGA improve significantly the real FF of Ooe Toroku road network of Kumamoto City, Japan about 21.62%
Face Recognition Using Holistic Features and Linear Discriminant Analysis Simplification
This paper proposes an alternative approach to face recognition algorithm that is based on global/holistic features of face image and simplified linear discriminant analysis (LDA). The proposed method can overcome main problems of the conventional LDA in terms of large processing time for retraining when a new class data is registered into the training data set. The holistic features of face image are proposed as dimensional reduction of raw face image. While, the simplified LDA which is the redefinition of between class scatter using constant global mean assignment is proposed to decrease time complexity of retraining process. To know the performance of the proposed method, several experiments were performed using several challenging face databases: ORL, YALE, ITS-Lab, INDIA, and FERET database. Furthermore, we compared the developed algorithm experimental results to the best traditional subspace methods such as DLDA, 2DLDA, (2D)2DLDA, 2DPCA, and (2D)22DPCA. The experimental results show that the proposed method can be solve the retraining problem of the conventional LDA indicated by requiring shorted retraining time and stable recognition rate
Face Recognition Using Holistic Features and Within Class Scatter-Based PCA
The Principle Component Analysis (PCA) and itsvariations are the most popular approach for features clustering,which is mostly implemented for face recognition. The optimumprojection matrix of the PCA is typically obtained by eigenanalysisof global covariance matrix. However, the projection datausing the PCA are lack of discriminatory power. This problem iscaused by removing the null space of data scatter that containsmuch discriminant information. To solve this problem, we presentalternative strategy to the PCA called alternative PCA, whichobtains the optimum projection matrix from within class scatterinstead of global covariance matrix. This algorithm not onlyprovides better features clustering than that of common PCA(CPCA) but also can overcome the retraining problem of theCPCA. In this paper, this algorithm is applied for face recognitionwith the holistic features of face image, which has compact sizeand powerful energy compactness as dimensional reduction ofthe raw face image. From the experimental results, the proposedmethod provides better performance for both recognition rateand accuracy parameters than those of CPCA and its variationswhen the tests were carried out using data from several databasessuch as ITS-LAB., INDIA, ORL, and FERET
Fast pornographic image recognition using compact holistic features and multi-layer neural network
The paper presents an alternative fast pornographic image recognition using compact holistic features and multi-layer neural network (MNN). The compact holistic features of pornographic images, which are invariant features against pose and scale, is extracted by shape and frequency analysis on pornographic images under skin region of interests (ROIs). The main objective of this work is to design pornographic recognition scheme which not only can improve performances of existing methods (i.e., methods based on skin probability, scale invariant feature transform, eigenporn, and Multilayer-Perceptron and Neuro-Fuzzy (MP-NF)) but also can works fast for recognition. The experimental outcome display that our proposed system can improve 0.3% of accuracy and reduce 6.60% the false negative rate (FNR) of the best existing method (skin probability and eigenporn on YCbCr, SEP), respectively. Additionally, our proposed method also provides almost similar robust performances to the MP-NF on large size dataset. However, our proposed method needs short recognition time by about 0.021 seconds per image for both tested datasets
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