A FRAMEWORK FOR ARABIC SENTIMENT ANALYSIS USING MACHINE LEARNING CLASSIFIERS

International audienceIn recent years, the use of Internet and online comments, expressed in natural language text, have increased significantly. However, it is difficult for humans to read all these comments and classify them appropriately. Consequently, an automatic approach is required to classify the unstructured data. In this paper, we propose a framework for Arabic language comprising of three steps: pre-processing, feature extraction and machine learning classification. The main aim of the proposed framework is to exploit the combination of different Arabic linguistic features. We evaluate the framework using two benchmark Arabic tweets datasets (ASTD, ATA), which enable sentiment polarity detection in general Arabic and Jordanian dialects. Comparative simulation results show that machine learning classifiers such as Support Vector Machine (SVM), Naive Bayes, MultiLayer Perceptron (MLP) and Logistic Regression-based produce the best performance by using a combination of n-gram features from Arabic tweets datasets. Finally, we evaluate the performance of our proposed framework using an Ensemble classifier approach, with promising results

Grapevine yield estimation using image analysis for the variety Arinto

Mestrado em Engenharia de Viticultura e Enologia (Double Degree) / Instituto Superior de Agronomia. Universidade de Lisboa / Faculdade de Ciências. Universidade do PortoYield estimation can lead to difficulties in the vineyard and winery, if it is done inaccurately following wrong procedures, doing a non-representative sampling or for the human error. Moreover, the traditional yield estimation methods are time consuming and destructive because they need someone that goes into the vineyard to count the yield components and that take out from the vineyard inflorescence or bunches to count and weight the flowers and the berries. To avoid these problems and the errors that can occur on this way, the development and application of new and innovative techniques to estimate the yield through the analysis of RGB images taken under field conditions are under study from different groups of research. In our research work we’ve studied the application of counting the yield components in the images throughout all the growing season. Furthermore, we’ve studied two different algorithms that starting from the survey of canopy porosity and/or visible bunches area, can help to do an estimation of the yield. The most promising yield estimation, based on the counting of the yield components done through image analysis, was found to be at the phenological stage of four leaves out, which shown a mean absolute percent error (MA%E) of 32 ± 2% and an correlaion coefficient (r Obs,Est) between observed and estimated shoots of 0.62. The two algorithms used different models: for estimating the area of the bunches covered by leaves and to estimate the weight of the bunches per linear canopy meter. When the area of the bunches without leaf occlusion was estimated, an average percentage of occlusion generated by the bunches on the other bunches of 8%, 6% and 12% respectively at pea size, veraison and maturation, was used to estimate the total area of the bunches. When the total area of the bunches per linear canopy meter was estimated the two models to estimate the grape weight were used. Finally, to estimate the weight at harvest, the growth factors of 6.6 and 1.7 respectively, at pea size and veraison were used. The first algorithm shown a MA%E, between the estimated and observed values of yield, of - 33.59%, -9.24% and -11.25%, instead the second algorithm shown a MA%E of -6.81%, -1.35% and 0.01% respectively at pea-size, veraison and maturationN/

A Big Data Analytics Method for Tourist Behaviour Analysis

© 2016 Elsevier B.V. Big data generated across social media sites have created numerous opportunities for bringing more insights to decision-makers. Few studies on big data analytics, however, have demonstrated the support for strategic decision-making. Moreover, a formal method for analysing social media-generated big data for decision support is yet to be developed, particularly in the tourism sector. Using a design science research approach, this study aims to design and evaluate a ‘big data analytics’ method to support strategic decision-making in tourism destination management. Using geotagged photos uploaded by tourists to the photo-sharing social media site, Flickr, the applicability of the method in assisting destination management organisations to analyse and predict tourist behavioural patterns at specific destinations is shown, using Melbourne, Australia, as a representative case. Utility was confirmed using both another destination and directly with stakeholder audiences. The developed artefact demonstrates a method for analysing unstructured big data to enhance strategic decision making within a real problem domain. The proposed method is generic, and its applicability to other big data streams is discussed

A Big Data Analytics Method for Tourist Behaviour Analysis

© 2016 Elsevier B.V. Big data generated across social media sites have created numerous opportunities for bringing more insights to decision-makers. Few studies on big data analytics, however, have demonstrated the support for strategic decision-making. Moreover, a formal method for analysing social media-generated big data for decision support is yet to be developed, particularly in the tourism sector. Using a design science research approach, this study aims to design and evaluate a ‘big data analytics’ method to support strategic decision-making in tourism destination management. Using geotagged photos uploaded by tourists to the photo-sharing social media site, Flickr, the applicability of the method in assisting destination management organisations to analyse and predict tourist behavioural patterns at specific destinations is shown, using Melbourne, Australia, as a representative case. Utility was confirmed using both another destination and directly with stakeholder audiences. The developed artefact demonstrates a method for analysing unstructured big data to enhance strategic decision making within a real problem domain. The proposed method is generic, and its applicability to other big data streams is discussed

Development of a new non-invasive vineyard yield estimation method based on image analysis

Doutoramento em Engenharia Agronómica / Instituto Superior de Agronomia. Universidade de LisboaPredicting vineyard yield with accuracy can provide several advantages to the whole vine and wine industry. Today this is majorly done using manual and sometimes destructive methods, based on bunch samples. Yield estimation using computer vision and image analysis can potentially perform this task extensively, automatically, and non-invasively. In the present work this approach is explored in three main steps: image collection, occluded fruit estimation and image traits conversion to mass. On the first step, grapevine images were collected in field conditions along some of the main grapevine phenological stages. Visible yield components were identified in the image and compared to ground truth. When analyzing inflorescences and bunches, more than 50% were occluded by leaves or other plant organs, on three cultivars. No significant differences were observed on bunch visibility after fruit set. Visible bunch projected area explained an average of 49% of vine yield variation, between veraison and harvest. On the second step, vine images were collected, in field conditions, with different levels of defoliation intensity at bunch zone. A regression model was computed combining canopy porosity and visible bunch area, obtained via image analysis, which explained 70-84% of bunch exposure variation. This approach allowed for an estimation of the occluded fraction of bunches with average errors below |10|%. No significant differences were found between the model’s output at veraison and harvest. On the last step, the conversion of bunch image traits into mass was explored in laboratory and field conditions. In both cases, cultivar differences related to bunch architecture were found to affect weight estimation. A combination of derived variables which included visible bunch area, estimated total bunch area, visible bunch perimeter, visible berry number and bunch compactness was used to estimate yield on undisturbed grapevines. The final model achieved a R2 = 0.86 between actual and estimated yield (n = 213). If performed automatically, the final approach suggested in this work has the potential to provide a non-invasive method that can be performed accurately across whole vineyards.N/

Cloud Computing cost and energy optimization through Federated Cloud SoS

2017 Fall.Includes bibliographical references.The two most significant differentiators amongst contemporary Cloud Computing service providers have increased green energy use and datacenter resource utilization. This work addresses these two issues from a system's architectural optimization viewpoint. The proposed approach herein, allows multiple cloud providers to utilize their individual computing resources in three ways by: (1) cutting the number of datacenters needed, (2) scheduling available datacenter grid energy via aggregators to reduce costs and power outages, and lastly by (3) utilizing, where appropriate, more renewable and carbon-free energy sources. Altogether our proposed approach creates an alternative paradigm for a Federated Cloud SoS approach. The proposed paradigm employs a novel control methodology that is tuned to obtain both financial and environmental advantages. It also supports dynamic expansion and contraction of computing capabilities for handling sudden variations in service demand as well as for maximizing usage of time varying green energy supplies. Herein we analyze the core SoS requirements, concept synthesis, and functional architecture with an eye on avoiding inadvertent cascading conditions. We suggest a physical architecture that diminishes unwanted outcomes while encouraging desirable results. Finally, in our approach, the constituent cloud services retain their independent ownership, objectives, funding, and sustainability means. This work analyzes the core SoS requirements, concept synthesis, and functional architecture. It suggests a physical structure that simulates the primary SoS emergent behavior to diminish unwanted outcomes while encouraging desirable results. The report will analyze optimal computing generation methods, optimal energy utilization for computing generation as well as a procedure for building optimal datacenters using a unique hardware computing system design based on the openCompute community as an illustrative collaboration platform. Finally, the research concludes with security features cloud federation requires to support to protect its constituents, its constituents tenants and itself from security risks

Essays on Machine Learning in Risk Management, Option Pricing, and Insurance Economics

Dealing with uncertainty is at the heart of financial risk management and asset pricing. This cumulative dissertation consists of four independent research papers that study various aspects of uncertainty, from estimation and model risk over the volatility risk premium to the measurement of unobservable variables. In the first paper, a non-parametric estimator of conditional quantiles is proposed that builds on methods from the machine learning literature. The so-called leveraging estimator is discussed in detail and analyzed in an extensive simulation study. Subsequently, the estimator is used to quantify the estimation risk of Value-at-Risk and Expected Shortfall models. The results suggest that there are significant differences in the estimation risk of various GARCH-type models while in general estimation risk for the Expected Shortfall is higher than for the Value-at-Risk. In the second paper, the leveraging estimator is applied to realized and implied volatility estimates of US stock options to empirically test if the volatility risk premium is priced in the cross-section of option returns. A trading strategy that is long (short) in a portfolio with low (high) implied volatility conditional on the realized volatility yields average monthly returns that are economically and statistically significant. The third paper investigates the model risk of multivariate Value-at-Risk and Expected Shortfall models in a comprehensive empirical study on copula GARCH models. The paper finds that model risk is economically significant, especially high during periods of financial turmoil, and mainly due to the choice of the copula. In the fourth paper, the relation between digitalization and the market value of US insurers is analyzed. Therefore, a text-based measure of digitalization building on the Latent Dirichlet Allocation is proposed. It is shown that a rise in digitalization efforts is associated with an increase in market valuations.:1 Introduction 1.1 Motivation 1.2 Conditional quantile estimation via leveraging optimal quantization 1.3 Cross-section of option returns and the volatility risk premium 1.4 Marginals versus copulas: Which account for more model risk in multivariate risk forecasting? 1.5 Estimating the relation between digitalization and the market value of insurers 2 Conditional Quantile Estimation via Leveraging Optimal Quantization 2.1 Introduction 2.2 Optimal quantization 2.3 Conditional quantiles through leveraging optimal quantization 2.4 The hyperparameters N, λ, and γ 2.5 Simulation study 2.6 Empirical application 2.7 Conclusion 3 Cross-Section of Option Returns and the Volatility Risk Premium 3.1 Introduction 3.2 Capturing the volatility risk premium 3.3 Empirical study 3.4 Robustness checks 3.5 Conclusion 4 Marginals Versus Copulas: Which Account for More Model Risk in Multivariate Risk Forecasting? 4.1 Introduction 4.2 Market risk models and model risk 4.3 Data 4.4 Analysis of model risk 4.5 Model risk for models in the model confidence set 4.6 Model risk and backtesting 4.7 Conclusion 5 Estimating the Relation Between Digitalization and the Market Value of Insurers 5.1 Introduction 5.2 Measuring digitalization using LDA 5.3 Financial data & empirical strategy 5.4 Estimation results 5.5 Conclusio

Untangling hotel industry’s inefficiency: An SFA approach applied to a renowned Portuguese hotel chain

The present paper explores the technical efficiency of four hotels from Teixeira Duarte Group - a renowned Portuguese hotel chain. An efficiency ranking is established from these four hotel units located in Portugal using Stochastic Frontier Analysis. This methodology allows to discriminate between measurement error and systematic inefficiencies in the estimation process enabling to investigate the main inefficiency causes. Several suggestions concerning efficiency improvement are undertaken for each hotel studied.info:eu-repo/semantics/publishedVersio

Teaching Crossroads: 8th IPB Erasmus Week

We are proud to present the second number of Teaching Crossroads, within the 8th IPB Erasmus week which took place in May 2012. This publication is the result of the papers delivered during our Erasmus Week that is becoming increasingly popular among teaching and non-teaching staff from several Erasmus partner Universities. Similarly to last year, we are continuing the publication of Teaching Crossroads whose main purpose is to reach students and teaching staff of the IPB (Polytechnic Institute of Bragança) and of other IPB partner universities. With this in view, the authors also made an attempt to present material in a manner which can be readily grasped by students and non-specialists. Likewise, we also believe it is important to have a written register of what is being studied by some researchers in Europe and make it available to students. Bearing in mind the open spirit of this publication, everyone is invited to participate with their papers delivered during the Erasmus Week at the IPB. The result was pleasantly rewarding as we had enthusiastic participants who very willingly made their texts available for publication. The organisation of the Erasmus week has been a tradition since started in 2005 aiming at a more efficient collaboration with our European partners so that they would become more familiar with the IPB campus, its schools, the city and the region. During the IPB Erasmus Week, the Institute organises teaching and staff training (STT) and the seminars arranged under Staff Teaching Assignment (STA) that are scheduled and introduced in the regular timetable of Bachelors and Masters’ degrees classes. Having now participated in the Erasmus mobility programme for more than twelve years, the IPB is acknowledged as one of the Portuguese institutions that promotes students and teaching mobility the most, positioning IPB on the top of the European HEIs and on a high level in the current international scene. The review of these articles has been thorough, yet some unexpected flaws may still occur. Nevertheless, the content of the texts remains intact, without distorting the aims of the texts, and the references are the authors’ own responsibility. Therefore, we accept no liabilities for any error or theoretical inconsistency or any missing information. The research areas are quite multidisciplinary, touching on areas as different as business sciences and law, agricultural sciences and natural resources, chemistry, multimedia and education. These areas comply with the areas of study that the IPB has on offer. This publication is hence rather beneficial for our students, as well as teachers and researchers. Ziemowit Kukulski, with his customary precision, expands on a topic that is truly current and relevant nowadays: ‘The elimination of double taxation in juridical sense from Polish perspective’. Notwithstanding the fact that the study focused on a particular country, the author is also concerned with comparing both the Polish and the Portuguese juridical taxation framework. Rosa Vásquez presents a study on how the environment plays an important role in the economy and can contribute to making the business sector more dynamic. Emphasising the importance of state policies that affect the environment, her text outlines the different instruments available to public administration in order to enable environmental control of productive activities and promote good conduct in favour of environmental conservation. Bodgan Vlad Avarvarei presents the results of an analysis of commodity for some yoghurt assortments sold on Iasi market, in Romania. The author also aims to inform the consumers regarding not only all the information which must be marked on, such as fat content, nutritive value, shelf life, storage temperature, etc., but also to give some hints on the product design. Mario de la Fuente Lloreda gives a lesson on different ways of Spanish viticulture, exposing examples of one of the most emblematic D.O. (denominación de origen, i.e. protected designation of origin) quality brands and their evolution up to today. Igor Barényi’s text delves into spectral analysis, focusing on the description of several spectroscopic methods to examine chemical composition of metal and alloys. Esteban Galán-Cubillo takes us on a tour to the use of systems of virtual scenography, along with the use of other digital technologies. Cláudia Martins’s text gives us a very insightful glimpse on Portuguese meteorological adages and proverbs bearing the highly suggestive title ‘Nine months of winter, three months of scorching hell’. Besides that, the author also presents a thorough linguistic explanation on fixed language, ranging from collocations to idiomatic expressions, based on several keynote authors, with a particular focus on pragmatic phrases, i.e. proverbs and adages. Jan Michalko makes an introduction to Cyber Space Economics and its relevance for such an important area as education or even training of citizens as it is in the case of public services for increasing levels of e-government. The author also emphasises the importance of Internet applications that provide a number of opportunities for education, communication and business. Slawomir Sztajer presents a deep reflection on religion, establishing a link between cognition and religion. The author expands on this new approach of religion, explaining and interpreting religious phenomena from the perspective of cognitive science. The ingredients for a gainful and stimulating reading are now served. We hope that this publication works for the interest of many students and teachers who find here information for their own studies and learn a bit more about the countries referred to here, sharing learning experiences and scientific knowledge, as well as cultural heritage. That is also the essence of the Erasmus programme