2,049 research outputs found
Analysis of Segmentation Parameters Effect towards Parallel Processing Time on Fuzzy C Means Algorithm
Fuzzy C Means algorithm or FCM is one of many clustering algorithms that has better accuracy to solve problems related to segmentation. Its application is almost in every aspects of life and many disciplines of science. However, this algorithm has some shortcomings, one of them is the large amount of processing time consumption. This research conducted mainly to do an analysis about the effect of segmentation parameters towards processing time in sequential and parallel. The other goal is to reduce the processing time of segmentation process using parallel approach. Parallel processing applied on Nvidia GeForce GT540M GPU using CUDA v8.0 framework. The experiment conducted on natural RGB color image sized 256x256 and 512x512. The settings of segmentation parameter values were done as follows, weight in range (2-3), number of iteration (50-150), number of cluster (2-8), and error tolerance or epsilon (0.1 – 1e-06). The results obtained by this research as follows, parallel processing time is faster 4.5 times than sequential time with similarity level of image segmentations generated both of processing types is 100%. The influence of segmentation parameter values towards processing times in sequential and parallel can be concluded as follows, the greater value of weight parameter then the sequential processing time becomes short, however it has no effects on parallel processing time. For iteration and cluster parameters, the greater their values will make processing time consuming in sequential and parallel become large. Meanwhile the epsilon parameter has no effect or has an unpredictable tendency on both of processing time
Techniques for clustering gene expression data
Many clustering techniques have been proposed for the analysis of gene expression data obtained from microarray experiments. However, choice of suitable method(s) for a given experimental dataset is not straightforward. Common approaches do not translate well and fail to take account of the data profile. This review paper surveys state of the art applications which recognises these limitations and implements procedures to overcome them. It provides a framework for the evaluation of clustering in gene expression analyses. The nature of microarray data is discussed briefly. Selected examples are presented for the clustering methods considered
An MS Windows prototype for automatic general purpose image-based flaw detection
Flaw detection plays a crucial role in many industries to make sure that the products meet the specified quality requirements. When making for example a car it is important that all the parts satisfy certain quality standards to make sure the consumer buys a car that is safe to operate. A crack or another weakness in a crucial part can be catastrophic. To make sure their cars are as safe as possible, car manufacturers are conducting thorough testing of crucial parts. Similar tests are done in a wide variety of industries, and these quality controls are often referred to as flaw detection. Any cracks, voids, or other weaknesses that can cause danger are called flaws. Flaw detection is often done, or preferred done, in real time-- in an assembly line fashion. An important constraint, in addition to reliability, is therefore speed. The techniques used in these tests varies. Common techn~ques are ultrasonic waves (1-D or 2-D), eddy current imaging, x-ray imaging, thermal imaging, and fluorescent penetrent imaging. In this thesis I will discuss automatic general purpose image-based flaw detection. Automatic means that the flaw detection is performed without human supervision, and general purpose means that the inspection is not tailored to a specific task (i.e. one particular flaw in one particular type of object), but is ideally applicable to any detection problem
The k-means clustering technique: General considerations and implementation in Mathematica
Data clustering techniques are valuable tools for researchers working with large databases of multivariate data. In this tutorial, we present a simple yet powerful one: the k-means clustering technique, through three different algorithms: the Forgy/Lloyd, algorithm, the MacQueen algorithm and the Hartigan and Wong algorithm. We then present an implementation in Mathematica and various examples of the different options available to illustrate the application of the technique
Brokerage Platform for Media Content Recommendation
Near real time media content personalisation is nowadays a major challenge involving media content sources, distributors and viewers. This paper describes an approach to seamless recommendation, negotiation and transaction of personalised media content. It adopts an integrated view of the problem by proposing, on the business-to-business (B2B) side, a brokerage platform to negotiate the media items on behalf of the media content distributors and sources, providing viewers, on the business-to-consumer (B2C) side, with a personalised electronic programme guide (EPG) containing the set of recommended items after negotiation. In this setup, when a viewer connects, the distributor looks up and invites sources to negotiate the contents of the viewer personal EPG. The proposed multi-agent brokerage platform is structured in four layers, modelling the registration, service agreement, partner lookup, invitation as well as item recommendation, negotiation and transaction stages of the B2B processes. The recommendation service is a rule-based switch hybrid filter, including six collaborative and two content-based filters. The rule-based system selects, at runtime, the filter(s) to apply as well as the final set of recommendations to present. The filter selection is based on the data available, ranging from the history of items watched to the ratings and/or tags assigned to the items by the viewer. Additionally, this module implements (i) a novel item stereotype to represent newly arrived items, (ii) a standard user stereotype for new users, (iii) a novel passive user tag cloud stereotype for socially passive users, and (iv) a new content-based filter named the collinearity and proximity similarity (CPS). At the end of the paper, we present off-line results and a case study describing how the recommendation service works. The proposed system provides, to our knowledge, an excellent holistic solution to the problem of recommending multimedia contents
Peak annotation and data analysis software tools for mass spectrometry imaging
La metabolòmica espacial és la disciplina que estudia les imatges de les distribucions de compostos químics de baix
pes (metabòlits) a la superfície dels teixits biològics per revelar interaccions entre molècules. La imatge
d'espectrometria de masses (MSI) és actualment la tècnica principal per obtenir informació d'imatges moleculars per a
la metabolòmica espacial. MSI és una tecnologia d'imatges moleculars sense marcador que produeix espectres de
masses que conserven les estructures espacials de les mostres de teixit. Això s'aconsegueix ionitzant petites porcions
d'una mostra (un píxel) en un ràster definit a través de tota la seva superfície, cosa que dona com a resultat una
col·lecció d'imatges de distribució de ions (registrades com a relacions massa-càrrega (m/z)) sobre la mostra. Aquesta
tesi té com a objectius desenvolupar eines computacionals per a l'anotació de pics de MSI i el disseny de fluxos de
treball per a l'anàlisi estadística i multivariant de dades MSI, inclosa la segmentació espacial. El treball realitzat en
aquesta tesi es pot separar clarament en dues parts. En primer lloc, el desenvolupament d'una eina d'anotació de pics
d'isòtops i adductes adequada per facilitar la identificació de compostos de rang de massa baix. Ara podem trobar
fàcilment ions monoisotòpics als nostres conjunts de dades MSI gràcies al paquet de programari rMSIannotation. En
segon lloc, el desenvolupament de eines de programari per a l’anàlisi de dades i la segmentació espacial basades en
soft clustering per a dades MSI.La metabolómica espacial es la disciplina que estudia las imágenes de las distribuciones de compuestos químicos de
bajo peso (metabolitos) en la superficie de los tejidos biológicos para revelar interacciones entre moléculas. Las
imágenes de espectrometría de masas (MSI) es actualmente la principal técnica para obtener información de
imágenes moleculares para la metabolómica espacial. MSI es una tecnología de imágenes moleculares sin marcador
que produce espectros de masas que conservan las estructuras espaciales de las muestras de tejido. Esto se logra
ionizando pequeñas porciones de una muestra (un píxel) en un ráster definido a través de toda su superficie, lo que da
como resultado una colección de imágenes de distribución de iones (registradas como relaciones masa-carga (m/z))
sobre la muestra. Esta tesis tiene como objetivo desarrollar herramientas computacionales para la anotación de picos
en MSI y en el diseño de flujos de trabajo para el análisis estadístico y multivariado de datos MSI, incluida la
segmentación espacial. El trabajo realizado en esta tesis se puede separar claramente en dos partes. En primer lugar,
el desarrollo de una herramienta de anotación de picos de isótopos y aductos adecuada para facilitar la identificación
de compuestos de bajo rango de masa. Ahora podemos encontrar fácilmente iones monoisotópicos en nuestros
conjuntos de datos MSI gracias al paquete de software rMSIannotation.Spatial metabolomics is the discipline that studies the images of the distributions of low weight chemical compounds
(metabolites) on the surface of biological tissues to unveil interactions between molecules. Mass spectrometry imaging
(MSI) is currently the principal technique to get molecular imaging information for spatial metabolomics. MSI is a labelfree
molecular imaging technology that produces mass spectra preserving the spatial structures of tissue samples. This
is achieved by ionizing small portions of a sample (a pixel) in a defined raster through all its surface, which results in a
collection of ion distribution images (registered as mass-to-charge ratios (m/z)) over the sample. This thesis is aimed to
develop computational tools for peak annotation in MSI and in the design of workflows for the statistical and
multivariate analysis of MSI data, including spatial segmentation. The work carried out in this thesis can be clearly
separated in two parts. Firstly, the development of an isotope and adduct peak annotation tool suited to facilitate the
identification of the low mass range compounds. We can now easily find monoisotopic ions in our MSI datasets thanks
to the rMSIannotation software package. Secondly, the development of software tools for data analysis and spatial
segmentation based on soft clustering for MSI data. In this thesis, we have developed tools and methodologies to
search for significant ions (rMSIKeyIon software package) and for the soft clustering of tissues (Fuzzy c-means
algorithm)
Review of Clustering Methods for Slow Coherency-Based Generator Grouping
Slow coherency is one of the most relevant concepts used in power systems dynamics to group generators that exhibit similar response to disturbances. Among the approaches developed for generator grouping based on slow coherency, clustering algorithms play a significant role. This paper reviews the clustering algorithms applied in model-based and data-driven approaches, highlighting the metrics used, the feature selection, the types of algorithms and the comparison among the results obtained considering simulated or measured data
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