2,254 research outputs found

    The role of credence attributes in consumer choices of sustainable fish products: A review

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    This review aims to assess consumer choices of sustainable fish products, considering a number of attributes that have been considered in the academic literature on this topic. In order to examine the effectiveness of sustainable labels, the research question was focused on the relation between sustainable fish labels and consumers’ willingness to pay (WTP). The findings showed how, overall, consumers have positive perceptions regarding sustainable fish products and show a willingness to pay a premium price for the attribute of sustainability. According to the results, the country of origin attribute was found to be the most important attribute in relation to consumer choice. The results indicated a high WTP for local fish products, relative to imported alternatives. Consumers prefer wild-caught fish for its perceived quality, better safety and health aspects, and taste perception than the farm-raised option. As for animal welfare, the results show that consumers are willing to pay a moderate premium price for products that have an improved fish welfare or those that avoid by-catch, such as products with eco-labels like “turtle safe”. With regard to organic labels, the studies identified a positive organic price premium for fish products. However, organic labels do not play a major role in consumer choice, when compared with other attributes

    Review of the State of the Art of Transfer Learning for Plant Leaf Diseases Detection

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    Plant leaf diseases can have a significantly negative influence on the quantity and quality of agricultural cultivation, as well as the safety of food production. Plant leaf diseases could potentially entirely prevent the harvest of grains in some situations. Therefore, it is extremely important from a pragmatic standpoint to look for quick, automatic, cheap, and accurate ways to detect plant leaf diseases. One of the well-known plant leaf disease detection approaches is deep learning. Deep learning has several drawbacks as a result of the huge amount of data required to train the network. When a dataset has inadequate photographs, performance falls. An approach called "Transfer Learning" is an extensively used method for addressing the shortcomings of a small dataset, the length of the training process, and improving the performance of the model. In this study, we investigated transfer learning for deep CNNs to improve the learning capability to recognize leaf disease. This survey focuses on categorizing and analyzing the recent developments in transfer learning for Deep CNN situations to enhance learning performance by reducing the need for extensive training data collecting

    Vision-based techniques for automatic marine plankton classification

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    Plankton are an important component of life on Earth. Since the 19th century, scientists have attempted to quantify species distributions using many techniques, such as direct counting, sizing, and classification with microscopes. Since then, extraordinary work has been performed regarding the development of plankton imaging systems, producing a massive backlog of images that await classification. Automatic image processing and classification approaches are opening new avenues for avoiding time-consuming manual procedures. While some algorithms have been adapted from many other applications for use with plankton, other exciting techniques have been developed exclusively for this issue. Achieving higher accuracy than that of human taxonomists is not yet possible, but an expeditious analysis is essential for discovering the world beyond plankton. Recent studies have shown the imminent development of real-time, in situ plankton image classification systems, which have only been slowed down by the complex implementations of algorithms on low-power processing hardware. This article compiles the techniques that have been proposed for classifying marine plankton, focusing on automatic methods that utilize image processing, from the beginnings of this field to the present day.Funding for open access charge: Universidad de Málaga / CBUA. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. The authors wish to thank Alonso Hernández-Guerra for his frm support in the development of oceanographic technology. Special thanks to Laia Armengol for her help in the domain of plankton. This study has been funded by Feder of the UE through the RES-COAST Mac-Interreg pro ject (MAC2/3.5b/314). We also acknowledge the European Union projects SUMMER (Grant Agreement 817806) and TRIATLAS (Grant Agreement 817578) from the Horizon 2020 Research and Innovation Programme and the Ministry of Science from the Spanish Government through the Project DESAFÍO (PID2020-118118RB-I00)

    Investigation of feature extraction algorithms and techniques for hyperspectral images.

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    Doctor of Philosophy (Computer Engineering). University of KwaZulu-Natal. Durban, 2017.Hyperspectral images (HSIs) are remote-sensed images that are characterized by very high spatial and spectral dimensions and nd applications, for example, in land cover classi cation, urban planning and management, security and food processing. Unlike conventional three bands RGB images, their high dimensional data space creates a challenge for traditional image processing techniques which are usually based on the assumption that there exists su cient training samples in order to increase the likelihood of high classi cation accuracy. However, the high cost and di culty of obtaining ground truth of hyperspectral data sets makes this assumption unrealistic and necessitates the introduction of alternative methods for their processing. Several techniques have been developed in the exploration of the rich spectral and spatial information in HSIs. Speci cally, feature extraction (FE) techniques are introduced in the processing of HSIs as a necessary step before classi cation. They are aimed at transforming the high dimensional data of the HSI into one of a lower dimension while retaining as much spatial and/or spectral information as possible. In this research, we develop semi-supervised FE techniques which combine features of supervised and unsupervised techniques into a single framework for the processing of HSIs. Firstly, we developed a feature extraction algorithm known as Semi-Supervised Linear Embedding (SSLE) for the extraction of features in HSI. The algorithm combines supervised Linear Discriminant Analysis (LDA) and unsupervised Local Linear Embedding (LLE) to enhance class discrimination while also preserving the properties of classes of interest. The technique was developed based on the fact that LDA extracts features from HSIs by discriminating between classes of interest and it can only extract C 1 features provided there are C classes in the image by extracting features that are equivalent to the number of classes in the HSI. Experiments show that the SSLE algorithm overcomes the limitation of LDA and extracts features that are equivalent to ii iii the number of classes in HSIs. Secondly, a graphical manifold dimension reduction (DR) algorithm known as Graph Clustered Discriminant Analysis (GCDA) is developed. The algorithm is developed to dynamically select labeled samples from the pool of available unlabeled samples in order to complement the few available label samples in HSIs. The selection is achieved by entwining K-means clustering with a semi-supervised manifold discriminant analysis. Using two HSI data sets, experimental results show that GCDA extracts features that are equivalent to the number of classes with high classi cation accuracy when compared with other state-of-the-art techniques. Furthermore, we develop a window-based partitioning approach to preserve the spatial properties of HSIs when their features are being extracted. In this approach, the HSI is partitioned along its spatial dimension into n windows and the covariance matrices of each window are computed. The covariance matrices of the windows are then merged into a single matrix through using the Kalman ltering approach so that the resulting covariance matrix may be used for dimension reduction. Experiments show that the windowing approach achieves high classi cation accuracy and preserves the spatial properties of HSIs. For the proposed feature extraction techniques, Support Vector Machine (SVM) and Neural Networks (NN) classi cation techniques are employed and their performances are compared for these two classi ers. The performances of all proposed FE techniques have also been shown to outperform other state-of-the-art approaches

    Assessment of graphene-based materials against the Substances of Very High Concern criteria

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    Recently, the nanomaterial carbon nanotubes was added to the Substitute It Now! (SIN) List managed by the International Chemical Secretariate (ChemSec). The SIN List considers the same hazard criteria for categorizing chemicals as so-called Substances of Very High Concern (SVHC) as the European chemical regulation REACH. In order to be considered as SVHC under REACH, a compound has to be identified as either: (i) carcinogenic; (ii) mutagenic; (iii) toxic to reproduction; (iv) persistent, bioaccumulative, and toxic; (v) very persistent and very bioaccumulative; or (vi) have properties that give rise to serious effects of an equivalent level of concern as points i-v. In this study, we evaluate another type of nanomaterial, namely graphene and other graphene-based materials (GBMs), and mirror current evidence of hazards and serious effects up against the SVHC criteria. The evaluation is based on a literature review of relevant studies identified in the scientific database Scopus (Elsevier B.V.) and previous review studies. The final corpus consisted of 30 studies that provided relevant information related to at least one of the SVHC criteria. No data was found on carcinogenicity, persistence, and endocrine disruption of GBMs. Studies on these criteria are therefore highly recommended. One study indicates that GBMs are not bioaccumulating, but more studies would be needed before a robust conclusion can be reached regarding this criterion. Several studies on toxicity were identified, with results clearly indicating that GBMs should not be classified as toxic. Several studies on reproductive toxicity, were also identified, of which some reported reproductive toxicity in mice. Finally, a number of studies observed genotoxic effects of GBMs, in some cases also explicit mutations. Although there are indications of reproductive toxicity and mutagenicity of GBMs, the current state of knowledge is limited. Detailed assessments of whether some or all GBMs should be classified as toxic to reproduction and mutagenic are therefore recommended. In conclusion, the current scientific evidence is not deemed strong enough to classify GBMs as SVHC, but the toxicological literature should be continuously be monitored, especially with regards to reproductive effects

    Cluster analysis for outlier detection : A case study of applying unsupervised machine learning on diesel engine data

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    With the advent of modern data driven methods, engine manufacturers and maintainers are attempting to pivot from corrective to predictive maintenance. One way to achieve this goal is to install sensors on the engine and look for anomalies in the data patterns it produces. Companies such as Wärtsilä that provide condition monitoring services use the Fast Fourier Transform to manually look for anomalies in the data. The Edge-project is an industrial research project involving institutions such as universities and private companies, with the goal of developing technical solutions and edge analytics for autonomous devices and vessels. Several papers and theses have been written as a result of the project, using techniques such as autoencoders to perform anomaly detection on data produced by sensors on a diesel engine. This thesis explores the use of cluster analysis for anomaly detection on diesel engine data from the Edge-project. Finding clusters could potentially represent different states of the running engine, with anomalies being represented e.g. by data points far away from cluster centroids, or data points not belonging to any particular cluster. The techniques of K-means, DBSCAN and spectral clustering are used for assigning clusters, with silhouette coefficient and eigengap used as hyperparameter tuning heuristics. Distance from cluster centroids and reduced kernel density estimation are used to flag anomalies. T-SNE and Self-Organizing Maps are used as dimensionality reduction techniques to visualize the data into a 3-dimensional and 2-dimensional space, respectively. Results show that what data are flagged as anomalies is highly sensitive to the choice of algorithm and chosen hyperparameters. The different results suggest different data as anomaly candidates. Therefore, further evaluation is needed from subject matter experts to determine which one of the models provides the most interesting results. Further work could include building an ensemble model that combines the used approaches, which could flag certain areas of the data space as a high risk for being anomalous.Moottorien valmistajat ja ylläpitäjät pyrkivät siirtymään korjaavasta huollosta ennakoivaan huoltoon modernien datavetoisten menetelmien avulla. Tämä voidaan saavuttaa esimerkiksi asentamalla antureita moottoriin ja etsimällä poikkeavuuksia anturien tuottamasta datasta. Yritykset kuten Wärtsilä, jotka tarjoavat kunnonvalvontapalveluita etsivät datasta poikkeavuuksia manuaalisesti Fourier-muunnosten avulla. Edge-projekti on teollinen tutkimushanke, johon osallistuu mm. yliopistoja ja yksityisen sektorin yrityksiä, ja jonka tavoitteena on tuottaa teknisiä ratkaisuja ja reunalaskenta-analytiikkaa itseohjautuville laitteille, ajoneuvoille ja aluksille. Hankkeesta on kirjoitettu monia tutkimusartikkeleita ja opinnäytetöitä, joissa käytetään tekniikoita kuten syviä neuroverkkoja poikkeavuuksien havaitsemiseen dieselmoottoriin asennettujen anturien tuottamasta datasta. Tämä opinnäytetyö tutkii klusterianalyysiä menetelmänä poikkeavuuksien havaitsemiseen Edge-projektissa ajetun dieselmoottorin datasta. Klusterit voisivat mahdollisesti edustaa ajettavan moottorin eri tiloja, ja poikkeavuudet voisivat olla esim. kaukana klusterien keskipisteistä olevia datapisteitä, tai datapisteitä, jotka eivät kuulu mihinkään tiettyyn klusteriin. Työssä käytetään algoritmeja K-means, DBSCAN ja spektraaliklusterointia klusterien määrittämiseen, ja siluettikerrointa sekä ominaisväliä käytetään hyperparametrioptimoinnin heuristiikkoina. Poikkeavuuksien merkintään käytetään etäisyyttä klusterien keskipisteisiin sekä alennettua ydintiheysestimaattoria. T-SNE:tä ja itseorganisoituvaa karttaa käytetään datan ulottuvuuksien vähentämisen tekniikoina, jotta data voidaan visualisoida 3- ja 2-ulotteiseen avaruuteen. Tulokset osoittavat, että mikä data tulkitaan poikkeavana, riippuu vahvasti algoritmin ja sen hyperparametrien valinnasta. Menetelmien merkitsemät poikkeavuudet eroavat huomattavasti toisistaan. Tämän vuoksi vaaditaan aihealueen ammattilaisilta lisätutkimuksia, jotta voidaan päättää mikä malli luo mielenkiintoisimmat tulokset. Jatkokehitysideana voisi olla mallikokoelma, jossa yhdistyy tässä työssä käytetyt menetelmät, ja jonka tehtävänä olisi kartoittaa data-avaruuden eri alueiden riskit poikkeavuuksien sisältämiseen

    Predicting Collaboration: Risk, Power, and Dependence in the Gulf of Maine

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    Collaboration among natural resource organizations and users is touted by researchers as an effective approach to managing common pool resources. To understand how collaboration works, previous studies in organizational theory have identified three variables: power, dependence, and risk. Relationships between actors can be represented by these qualifications of resources or threats and may predict if those relationships are in conflict or asymmetric in power. In this study, the Gulf of Maine transboundary fishery management network relied upon a dyadic influenced survey to quantitatively capture the perception of communication ties between organizations. Four kinds of dependence and three types of risk were captured by respondent responses to be used in predictive and descriptive analysis. The patterns presented a network with low risk and high levels of dependence. Dependence and risk were able to significantly predict whether a relationship was in conflict or whether a relationship had feelings of power, with legitimacy and performance as higher rated indicators. The results suggest that policy makers and network designers should foster legitimacy and shun performance failures when evaluating the relationships among management networks
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