Search results for " processing"
showing 10 items of 7549 documents
Biophysical parameter estimation with adaptive Gaussian Processes
2009
We evaluate Gaussian Processes (GPs) for the estimation of biophysical parameters from acquired multispectral data. The standard GP formulation is used, and all hyperparameters (kernel parameters and noise variance) are optimized by maximizing the marginal likelihood. This gives rise to a fully-adaptive GP to data characteristics, both in terms of signal and noise properties. The good numerical results in the estimation of oceanic chlorophyll concentration and leaf membrane state confirm GPs as adequate, alternative non-parametric methods for biophysical parameter estimation. GPs are also analyzed by scrutinizing the predictive variance, the estimated noise variance, and the relevance of ea…
Hyperspectral Texture Metrology Based on Joint Probability of Spectral and Spatial Distribution
2021
International audience; Texture characterization from the metrological point of view is addressed in order to establish a physically relevant and directly interpretable feature. In this regard, a generic formulation is proposed to simultaneously capture the spectral and spatial complexity in hyperspectral images. The feature, named relative spectral difference occurrence matrix (RSDOM) is thus constructed in a multireference, multidirectional, and multiscale context. As validation, its performance is assessed in three versatile tasks. In texture classification on HyTexiLa, content-based image retrieval (CBIR) on ICONES-HSI, and land cover classification on Salinas, RSDOM registers 98.5% acc…
Quantitative image analysis of the chromatolysis in rat facial and hypoglossal motoneurons following axotomy with and without reinnervation.
1996
Image analysis was used to quantify the time course of chromatolysis in regenerating and degenerating motoneurons. Following facial-facial, hypoglossal-hypoglossal nerve suture, or resection of facial and hypoglossal nerves with postoperative survival times of 4 h to 112 days, the texture of the Nissl substance of facial and hypoglossal motoneurons was analyzed on both sides of the brainstem in paraffin serial sections with a VIDASplus image analyzer. In this quantitative study of 149 Wistar rats, alterations of the Nissl substance were measured that were statistically significant but not yet visible to the human eye. Chromatolysis started significantly as early as 8 h and was not fully rev…
The use of texture analysis to study the time course of chromatolysis
1998
Image analysis of the textural feature entropy of the Nissl substance was used to monitor the time course of chromatolysis in regenerating hypoglossal motoneurons and degenerating facial motoneurons 4-112 days after hypoglossal-facial anastomosis in rats. Changes in the Nissl substance were detected that were not obvious on the basis of subjective judgement of the light-microscopical appearance of the neurons. Chromatolysis started 4 days post operation (dpo) and was not reversed at 112 dpo in both nuclei. The increase of chromatolysis was 14-28 dpo faster in the regenerating hypoglossal neurons than in degenerating facial neurons. Maximal chromatolysis was measured at 56-70 dpo in both nuc…
Measuring the Novelty of Natural Language Text Using the Conjunctive Clauses of a Tsetlin Machine Text Classifier
2020
Most supervised text classification approaches assume a closed world, counting on all classes being present in the data at training time. This assumption can lead to unpredictable behaviour during operation, whenever novel, previously unseen, classes appear. Although deep learning-based methods have recently been used for novelty detection, they are challenging to interpret due to their black-box nature. This paper addresses \emph{interpretable} open-world text classification, where the trained classifier must deal with novel classes during operation. To this end, we extend the recently introduced Tsetlin machine (TM) with a novelty scoring mechanism. The mechanism uses the conjunctive clau…
Nouvelles perspectives concernant la structure et la fonction du domaine carboxyl terminal de Hfq
2015
Accumulating evidence indicates that RNA metabolism components assemble into supramolecular cellular structures to mediate functional compartmentalization within the cytoplasmic membrane of the bacterial cell. This cellular compartmentalization could play important roles in the processes of RNA degradation and maturation. These components include Hfq, the RNA chaperone protein, which is involved in the post-transcriptional control of protein synthesis mainly by the virtue of its interactions with several small regulatory ncRNAs (sRNA). The Escherichia coli Hfq is structurally organized into two domains. An N-terminal domain that folds as strongly bent β-sheets within individual protomers to…
Do Current Domestic Gigabit Wireless Technologies Fulfill User Requirements for Ultra High Definition Videos?
2017
We present the results from a measurement-based performance evaluation of wireless networks based on IEEE 802.11n and IEEE 802.11ac standards in an indoor environment, with the aim to analyze their performance under high definition streaming video applications. We focus our study on analyzing the highest performance of these standards using off-the-shelf equipment, both with synthetic TCP and UDP traffic to measure the saturation throughput as well as high definition video streams. The measurements have been conducted in the student labs of our university and show good performance for streaming purposes in high definition and also ultra-high definition from a subjective video quality point …
Wireless Internet. 8th International Conference, WICON 2014, Lisbon, Portugal, November 13-14, 2014, Revised Selected Papers
2015
In this paper, the influence and improvement of the localization accuracy achieved using a fingerprint database with information coming from different channels and radio signal strength levels is evaluated. This study uses IEEE 802.15.4 networks with different power levels and carrier frequency channels in the 2.4 GHz band. Experimental results show that selecting part of this information with a cleverer data processing can provide similar or better localization accuracy than using the whole database.
Identifying Geographic Terms within Natural Language Text
2008
Masteroppgave i informasjons- og kommunikasjonsteknologi 2008 – Universitetet i Agder, Grimstad The huge amount of textual data available in digital form in today’s world increases the need for methods that facilitate ease of access and navigability. Automatic extraction of keywords from text bodies is one promising approach. However, the relevance of keywords are context dependent, and extracting relevant keywords often requires a semantic analysis, simply because words may have different meanings in different contexts. It is well-known that resolving such word sense ambiguity automatically can be very challenging. When the topic of interest is geographic information, important keywords wo…
WLAN 802.11 b/g interference into ZigBee networks
2008
Masteroppgave i informasjons- og kommunikasjonsteknologi 2008 – Universitetet i Agder, Grimstad ZigBee network as a low rate wireless personal area network (LR-WPANs) developed very fast nowadays. Since both ZigBee network and WLAN (802.11b/g) operate in the 2.4GHz unlicensed industrial scientific medical (ISM) frequency band, signal interference is possible to exist and result in signal degradation when devices are collocated in the same environment. This thesis analyzes, simulates and measures the interference and evaluates ZigBee network performance under the WLAN interference in terms of Packet Error Rate (PER) and Packet Loss Ratio (PLR). And the investigation emphasis of this thesis i…