3,249 research outputs found

    Monetary policy strategy in a global environment

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    This paper discusses the structural implications of real and financial globalisation, with the aim of drawing lessons for the conduct of monetary policy and, in particular, for the assessment of risks to price stability. The first conclusion of the paper is that globalisation may have played only a limited role in reducing inflation and output volatility in developed economies. Central banks should remain focused on their mandate to preserve price stability. However, the globalisation of financial markets over the last 25 years has had major implications for the conduct of monetary policy. Four elements characterise the new financial landscape: the decline in the “home bias”; the increase in the size of international financial transactions relative to transactions in goods and services; the increase in the number of countries adopting inflation targeting and currency peg monetary regimes; and the transformation of financial market microstructure. The paper argues that in this new environment monetary policy should systematically incorporate financial analysis into its assessment of the risks to price stability. Monetary policy should “lean against the wind” of asset price bubbles that could burst at a high cost and hinder the maintenance of macroeconomic and financial stability. Further, in view of the interlinkages among financial markets worldwide, macro-financial surveillance at the international level needs to be strengthened and monetary policymakers need to cooperate and exchange information on a wider scale and at a deeper level with financial supervisors. Finally, the paper reviews the rationale for a central bank to act (in concert with other central banks) as the ultimate provider of liquidity to financial markets in situations of extreme instability and market malfunctioning. A sudden and sharp liquidity drought in the market should be tackled with appropriate measures that could even go beyond the extraordinary refinancing of monetary and financial institutions. In these circumstances, the central bank should clearly communicate that the aim of its liquidity provision measures is to support the proper functioning of financial markets, and that they do not indicate a change in the monetary policy stance (“separation principle”). JEL Classification: E44, E58, F33, F42.Globalisation, Monetary policy, Asset prices, Financial markets.

    Web Data Extraction, Applications and Techniques: A Survey

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    Web Data Extraction is an important problem that has been studied by means of different scientific tools and in a broad range of applications. Many approaches to extracting data from the Web have been designed to solve specific problems and operate in ad-hoc domains. Other approaches, instead, heavily reuse techniques and algorithms developed in the field of Information Extraction. This survey aims at providing a structured and comprehensive overview of the literature in the field of Web Data Extraction. We provided a simple classification framework in which existing Web Data Extraction applications are grouped into two main classes, namely applications at the Enterprise level and at the Social Web level. At the Enterprise level, Web Data Extraction techniques emerge as a key tool to perform data analysis in Business and Competitive Intelligence systems as well as for business process re-engineering. At the Social Web level, Web Data Extraction techniques allow to gather a large amount of structured data continuously generated and disseminated by Web 2.0, Social Media and Online Social Network users and this offers unprecedented opportunities to analyze human behavior at a very large scale. We discuss also the potential of cross-fertilization, i.e., on the possibility of re-using Web Data Extraction techniques originally designed to work in a given domain, in other domains.Comment: Knowledge-based System

    HYPERLINK NETWORK SYSTEM AND IMAGE OF GLOBAL CITIES: WEBPAGES AND THEIR CONTENTS

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    A distinctive trend of globalization research is a conceptual expansion that mirrors the penetration of globalization in various aspects of life. The World Wide Web has become the ultimate platform to create and disseminate information in this era of globalization. Although the importance of web-based information is widely acknowledged, the use of this information in global city research is not significant yet. Therefore, the purpose of this research is to extend the concept of globalization to the efficiency of information networks and the thematic dimensionality of the conveyed images from webpages. To this end, 264 global and globalizing cities are selected. The city hyperlink networks are constructed from the web crawling results of each city, and hyperlink network analysis measures the effectiveness of these hyperlink networks. The textual contents are also extracted from the crawled webpages, and the thematic dimensionality of the textual contents is measured by quantified content analysis and multidimensional scaling. The efficiency of the hyperlink network in information flow is confirmed to be a new consideration that shapes the globality of cities. The cities with high efficiency of connections have faster and easier access, which means better structure for city image formation. Specifically, social networking websites are the center of this information flow. This means that social interactions on the Web play a crucial role to form the images of cities. Apart from the positivity and the negativity of the city image, the dimensionality of cities on the thematic space denotes how they are expressed, discussed, and shared on the Web. The image status based on dimensions of globalization is an important starting point to city branding. It is concluded that a research framework handling information networks and images simultaneously deepens the understanding of how the structure and the contents on the Web affect the formation and maintenance of global city networks. Overall, this research demonstrates the usefulness of information networks and images of cities on the Web to overcome data inconsistency and scarcity in global city research

    Seller Strategies on eBay

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    This paper analyzes seller characteristics and choices in approximately 1000 eBay auctions for a particular model of PDA. Seller characteristics include frequency of selling, reputation, and the qualities of the product sold. Seller choices include the length of the auction, information provided about the product, starting price, and whether to use a ‘Buy it Now’ option. We find that different types of sellers pursue systematically different strategies for how their items are offered, and we discuss the possible causes of these differences. For example, the two high volume sellers in our sample always use a combination of a ‘Buy it Now’ with a low starting price, while the many less frequent sellers use an array of pricing strategies. In addition, more highly rated sellers were somewhat more likely to provide more detailed product information, as well as secure payment options.

    Impersonation-as-a-Service: Characterizing the Emerging Criminal Infrastructure for User Impersonation at Scale

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    In this paper we provide evidence of an emerging criminal infrastructure enabling impersonation attacks at scale. Impersonation-as-a-Service (ImpaaS) allows attackers to systematically collect and enforce user profiles (consisting of user credentials, cookies, device and behavioural fingerprints, and other metadata) to circumvent risk-based authentication system and effectively bypass multi-factor authentication mechanisms. We present the ImpaaS model and evaluate its implementation by analysing the operation of a large, invite-only, Russian ImpaaS platform providing user profiles for more than 260000260'000 Internet users worldwide. Our findings suggest that the ImpaaS model is growing, and provides the mechanisms needed to systematically evade authentication controls across multiple platforms, while providing attackers with a reliable, up-to-date, and semi-automated environment enabling target selection and user impersonation against Internet users as scale.Comment: Presented at ACM CCS 2020. Appendix on "Deriving a Threat Model from Observation" available at https://michelecampobasso.github.io/publication/2020-11-10-impaa

    Big Data Computing for Geospatial Applications

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    The convergence of big data and geospatial computing has brought forth challenges and opportunities to Geographic Information Science with regard to geospatial data management, processing, analysis, modeling, and visualization. This book highlights recent advancements in integrating new computing approaches, spatial methods, and data management strategies to tackle geospatial big data challenges and meanwhile demonstrates opportunities for using big data for geospatial applications. Crucial to the advancements highlighted in this book is the integration of computational thinking and spatial thinking and the transformation of abstract ideas and models to concrete data structures and algorithms

    Predictive Analytics on Emotional Data Mined from Digital Social Networks with a Focus on Financial Markets

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    This dissertation is a cumulative dissertation and is comprised of five articles. User-Generated Content (UGC) comprises a substantial part of communication via social media. In this dissertation, UGC that carries and facilitates the exchange of emotions is referred to as “emotional data.” People “produce” emotional data, that is, they express their emotions via tweets, forum posts, blogs, and so on, or they “consume” it by being influenced by expressed sentiments, feelings, opinions, and the like. Decisions often depend on shared emotions and data – which again lead to new data because decisions may change behaviors or results. “Emotional Data Intelligence” ultimately seeks an answer to the question of how all the different emotions expressed in public online sources influence decision-making processes. The overarching research topic of this dissertation follows the question whether network structures and emotional sentiment data extracted from digital social networks contain predictive information or they are just noise. Underlying data was collected from different social media sources, such as Twitter, blogs, message boards, or online news and social networking sites, such as Xing. By means of methodologies of social network analysis (SNA), sentiment analysis, and predictive analysis the individual contributions of this dissertation study whether sentiment data from social media or online social networking structures can predict real-world behaviors. The focus lies on the analysis of emotional data and network structures and its predictive power for financial markets. With the formal construction of the data analyses methodologies introduced in the individual contributions this dissertation contributes to the theories of social network analysis, sentiment analysis, and predictive analytics

    Predicting online product sales via online reviews, sentiments, and promotion strategies

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    Purpose – The purpose of this paper is to investigate if online reviews (e.g. valence and volume), online promotional strategies (e.g. free delivery and discounts) and sentiments from user reviews can help predict product sales. Design/methodology/approach – The authors designed a big data architecture and deployed Node.js agents for scraping the Amazon.com pages using asynchronous input/output calls. The completed web crawling and scraping data sets were then preprocessed for sentimental and neural network analysis. The neural network was employed to examine which variables in the study are important predictors of product sales. Findings – This study found that although online reviews, online promotional strategies and online sentiments can all predict product sales, some variables are more important predictors than others. The authors found that the interplay effects of these variables become more important variables than the individual variables themselves. For example, online volume interactions with sentiments and discounts are more important than the individual predictors of discounts, sentiments or online volume. Originality/value – This study designed big data architecture, in combination with sentimental and neural network analysis that can facilitate future business research for predicting product sales in an online environment. This study also employed a predictive analytic approach (e.g. neural network) to examine the variables, and this approach is useful for future data analysis in a big data environment where prediction can have more practical implications than significance testing. This study also examined the interplay between online reviews, sentiments and promotional strategies, which up to now have mostly been examined individually in previous studies

    Enhancing Web Browsing Security

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    Web browsing has become an integral part of our lives, and we use browsers to perform many important activities almost everyday and everywhere. However, due to the vulnerabilities in Web browsers and Web applications and also due to Web users\u27 lack of security knowledge, browser-based attacks are rampant over the Internet and have caused substantial damage to both Web users and service providers. Enhancing Web browsing security is therefore of great need and importance.;This dissertation concentrates on enhancing the Web browsing security through exploring and experimenting with new approaches and software systems. Specifically, we have systematically studied four challenging Web browsing security problems: HTTP cookie management, phishing, insecure JavaScript practices, and browsing on untrusted public computers. We have proposed new approaches to address these problems, and built unique systems to validate our approaches.;To manage HTTP cookies, we have proposed an approach to automatically validate the usefulness of HTTP cookies at the client-side on behalf of users. By automatically removing useless cookies, our approach helps a user to strike an appropriate balance between maximizing usability and minimizing security risks. to protect against phishing attacks, we have proposed an approach to transparently feed a relatively large number of bogus credentials into a suspected phishing site. Using those bogus credentials, our approach conceals victims\u27 real credentials and enables a legitimate website to identify stolen credentials in a timely manner. to identify insecure JavaScript practices, we have proposed an execution-based measurement approach and performed a large-scale measurement study. Our work sheds light on the insecure JavaScript practices and especially reveals the severity and nature of insecure JavaScript inclusion and dynamic generation practices on the Web. to achieve secure and convenient Web browsing on untrusted public computers, we have proposed a simple approach that enables an extended browser on a mobile device and a regular browser on a public computer to collaboratively support a Web session. A user can securely perform sensitive interactions on the mobile device and conveniently perform other browsing interactions on the public computer

    Design and Evaluation of Web-Based Economic Indicators: A Big Data Analysis Approach

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    Tesis por compendio[ES] En la Era Digital, el creciente uso de Internet y de dispositivos digitales está transformando completamente la forma de interactuar en el contexto económico y social. Miles de personas, empresas y organismos públicos utilizan Internet en sus actividades diarias, generando de este modo una enorme cantidad de datos actualizados ("Big Data") accesibles principalmente a través de la World Wide Web (WWW), que se ha convertido en el mayor repositorio de información del mundo. Estas huellas digitales se pueden rastrear y, si se procesan y analizan de manera apropiada, podrían ayudar a monitorizar en tiempo real una infinidad de variables económicas. En este contexto, el objetivo principal de esta tesis doctoral es generar indicadores económicos, basados en datos web, que sean capaces de proveer regularmente de predicciones a corto plazo ("nowcasting") sobre varias actividades empresariales que son fundamentales para el crecimiento y desarrollo de las economías. Concretamente, tres indicadores económicos basados en la web han sido diseñados y evaluados: en primer lugar, un indicador de orientación exportadora, basado en un modelo que predice si una empresa es exportadora; en segundo lugar, un indicador de adopción de comercio electrónico, basado en un modelo que predice si una empresa ofrece la posibilidad de venta online; y en tercer lugar, un indicador de supervivencia empresarial, basado en dos modelos que indican la probabilidad de supervivencia de una empresa y su tasa de riesgo. Para crear estos indicadores, se han descargado una diversidad de datos de sitios web corporativos de forma manual y automática, que posteriormente se han procesado y analizado con técnicas de análisis Big Data. Los resultados muestran que los datos web seleccionados están altamente relacionados con las variables económicas objeto de estudio, y que los indicadores basados en la web que se han diseñado en esta tesis capturan en un alto grado los valores reales de dichas variables económicas, siendo por tanto válidos para su uso por parte del mundo académico, de las empresas y de los decisores políticos. Además, la naturaleza online y digital de los indicadores basados en la web hace posible proveer regularmente y de forma barata de predicciones a corto plazo. Así, estos indicadores son ventajosos con respecto a los indicadores tradicionales. Esta tesis doctoral ha contribuido a generar conocimiento sobre la viabilidad de producir indicadores económicos con datos online procedentes de sitios web corporativos. Los indicadores que se han diseñado pretenden contribuir a la modernización en la producción de estadísticas oficiales, así como ayudar a los decisores políticos y los gerentes de empresas a tomar decisiones informadas más rápidamente.[CA] A l'Era Digital, el creixent ús d'Internet i dels dispositius digitals està transformant completament la forma d'interactuar al context econòmic i social. Milers de persones, empreses i organismes públics utilitzen Internet a les seues activitats diàries, generant d'aquesta forma una enorme quantitat de dades actualitzades ("Big Data") accessibles principalment mitjançant la World Wide Web (WWW), que s'ha convertit en el major repositori d'informació del món. Aquestes empremtes digitals poden rastrejar-se i, si se processen i analitzen de forma apropiada, podrien ajudar a monitoritzar en temps real una infinitat de variables econòmiques. En aquest context, l'objectiu principal d'aquesta tesi doctoral és generar indicadors econòmics, basats en dades web, que siguen capaços de proveïr regularment de prediccions a curt termini ("nowcasting") sobre diverses activitats empresarials que són fonamentals per al creixement i desenvolupament de les economies. Concretament, tres indicadors econòmics basats en la web han sigut dissenyats i avaluats: en primer lloc, un indicador d'orientació exportadora, basat en un model que prediu si una empresa és exportadora; en segon lloc, un indicador d'adopció de comerç electrònic, basat en un model que prediu si una empresa ofereix la possibilitat de venda online; i en tercer lloc, un indicador de supervivència empresarial, basat en dos models que indiquen la probabilitat de supervivència d'una empresa i la seua tasa de risc. Per a crear aquestos indicadors, s'han descarregat una diversitat de dades de llocs web corporatius de forma manual i automàtica, que posteriorment s'han analitzat i processat amb tècniques d'anàlisi Big Data. Els resultats mostren que les dades web seleccionades estan altament relacionades amb les variables econòmiques objecte d'estudi, i que els indicadors basats en la web que s'han dissenyat en aquesta tesi capturen en un alt grau els valors reals d'aquestes variables econòmiques, sent per tant vàlids per al seu ús per part del món acadèmic, de les empreses i dels decisors polítics. A més, la naturalesa online i digital dels indicadors basats en la web fa possible proveïr regularment i de forma barata de prediccions a curt termini. D'aquesta forma, són avantatjosos en comparació als indicadors tradicionals. Aquesta tesi doctoral ha contribuït a generar coneixement sobre la viabilitat de produïr indicadors econòmics amb dades online procedents de llocs web corporatius. Els indicadors que s'han dissenyat pretenen contribuïr a la modernització en la producció d'estadístiques oficials, així com ajudar als decisors polítics i als gerents d'empreses a prendre decisions informades més ràpidament.[EN] In the Digital Era, the increasing use of the Internet and digital devices is completely transforming the way of interacting in the economic and social framework. Myriad individuals, companies and public organizations use the Internet for their daily activities, generating a stream of fresh data ("Big Data") principally accessible through the World Wide Web (WWW), which has become the largest repository of information in the world. These digital footprints can be tracked and, if properly processed and analyzed, could help to monitor in real time a wide range of economic variables. In this context, the main goal of this PhD thesis is to generate economic indicators, based on web data, which are able to provide regular, short-term predictions ("nowcasting") about some business activities that are basic for the growth and development of an economy. Concretely, three web-based economic indicators have been designed and evaluated: first, an indicator of firms' export orientation, which is based on a model that predicts if a firm is an exporter; second, an indicator of firms' engagement in e-commerce, which is based on a model that predicts if a firm offers e-commerce facilities in its website; and third, an indicator of firms' survival, which is based on two models that indicate the probability of survival of a firm and its hazard rate. To build these indicators, a variety of data from corporate websites have been retrieved manually and automatically, and subsequently have been processed and analyzed with Big Data analysis techniques. Results show that the selected web data are highly related to the economic variables under study, and the web-based indicators designed in this thesis are capturing to a great extent their real values, thus being valid for their use by the academia, firms and policy-makers. Additionally, the digital and online nature of web-based indicators makes it possible to provide timely, inexpensive predictions about the economy. This way, they are advantageous with respect to traditional indicators. This PhD thesis has contributed to generating knowledge about the viability of producing economic indicators with data coming from corporate websites. The indicators that have been designed are expected to contribute to the modernization of official statistics and to help in making earlier, more informed decisions to policy-makers and business managers.Blázquez Soriano, MD. (2019). Design and Evaluation of Web-Based Economic Indicators: A Big Data Analysis Approach [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/116836TESISCompendi
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