909 resultados para uncertain volatility


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The aim of the study is to developa novel robust controller based on sliding mode control technique for the hydraulic servo system with flexible load and for a flexible manipulator with the lift and jib hydraulic actuators. For the purpose of general control design, a dynamic model is derived describing the principle physical behavior for both the hydraulic servo system and the flexible hydraulic manipulator. The mechanism of hydraulic servo systems is described by basic mathematical equations of fluid powersystems and the dynamics of flexible manipulator is modeled by the assumed modemethod. The controller is constructed so as to track desired trajectories in the presence of model imprecision. Experimental and simulation results demonstratethat sliding mode control has benefits which can be used to guarantee stabilityin uncertain systems and improve the system performance and load tolerance.

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1. Introduction "The one that has compiled ... a database, the collection, securing the validity or presentation of which has required an essential investment, has the sole right to control the content over the whole work or over either a qualitatively or quantitatively substantial part of the work both by means of reproduction and by making them available to the public", Finnish Copyright Act, section 49.1 These are the laconic words that implemented the much-awaited and hotly debated European Community Directive on the legal protection of databases,2 the EDD, into Finnish Copyright legislation in 1998. Now in the year 2005, after more than half a decade of the domestic implementation it is yet uncertain as to the proper meaning and construction of the convoluted qualitative criteria the current legislation employs as a prerequisite for the database protection both in Finland and within the European Union. Further, this opaque Pan-European instrument has the potential of bringing about a number of far-reaching economic and cultural ramifications, which have remained largely uncharted or unobserved. Thus the task of understanding this particular and currently peculiarly European new intellectual property regime is twofold: first, to understand the mechanics and functioning of the EDD and second, to realise the potential and risks inherent in the new legislation in economic, cultural and societal dimensions. 2. Subject-matter of the study: basic issues The first part of the task mentioned above is straightforward: questions such as what is meant by the key concepts triggering the functioning of the EDD such as presentation of independent information, what constitutes an essential investment in acquiring data and when the reproduction of a given database reaches either qualitatively or quantitatively the threshold of substantiality before the right-holder of a database can avail himself of the remedies provided by the statutory framework remain unclear and call for a careful analysis. As for second task, it is already obvious that the practical importance of the legal protection providedby the database right is in the rapid increase. The accelerating transformationof information into digital form is an existing fact, not merely a reflection of a shape of things to come in the future. To take a simple example, the digitisation of a map, traditionally in paper format and protected by copyright, can provide the consumer a markedly easier and faster access to the wanted material and the price can be, depending on the current state of the marketplace, cheaper than that of the traditional form or even free by means of public lending libraries providing access to the information online. This also renders it possible for authors and publishers to make available and sell their products to markedly larger, international markets while the production and distribution costs can be kept at minimum due to the new electronic production, marketing and distributionmechanisms to mention a few. The troublesome side is for authors and publishers the vastly enhanced potential for illegal copying by electronic means, producing numerous virtually identical copies at speed. The fear of illegal copying canlead to stark technical protection that in turn can dampen down the demand for information goods and services and furthermore, efficiently hamper the right of access to the materials available lawfully in electronic form and thus weaken the possibility of access to information, education and the cultural heritage of anation or nations, a condition precedent for a functioning democracy. 3. Particular issues in Digital Economy and Information Networks All what is said above applies a fortiori to the databases. As a result of the ubiquity of the Internet and the pending breakthrough of Mobile Internet, peer-to-peer Networks, Localand Wide Local Area Networks, a rapidly increasing amount of information not protected by traditional copyright, such as various lists, catalogues and tables,3previously protected partially by the old section 49 of the Finnish Copyright act are available free or for consideration in the Internet, and by the same token importantly, numerous databases are collected in order to enable the marketing, tendering and selling products and services in above mentioned networks. Databases and the information embedded therein constitutes a pivotal element in virtually any commercial operation including product and service development, scientific research and education. A poignant but not instantaneously an obvious example of this is a database consisting of physical coordinates of a certain selected group of customers for marketing purposes through cellular phones, laptops and several handheld or vehicle-based devices connected online. These practical needs call for answer to a plethora of questions already outlined above: Has thecollection and securing the validity of this information required an essential input? What qualifies as a quantitatively or qualitatively significant investment? According to the Directive, the database comprises works, information and other independent materials, which are arranged in systematic or methodical way andare individually accessible by electronic or other means. Under what circumstances then, are the materials regarded as arranged in systematic or methodical way? Only when the protected elements of a database are established, the question concerning the scope of protection becomes acute. In digital context, the traditional notions of reproduction and making available to the public of digital materials seem to fit ill or lead into interpretations that are at variance with analogous domain as regards the lawful and illegal uses of information. This may well interfere with or rework the way in which the commercial and other operators have to establish themselves and function in the existing value networks of information products and services. 4. International sphere After the expiry of the implementation period for the European Community Directive on legal protection of databases, the goals of the Directive must have been consolidated into the domestic legislations of the current twenty-five Member States within the European Union. On one hand, these fundamental questions readily imply that the problemsrelated to correct construction of the Directive underlying the domestic legislation transpire the national boundaries. On the other hand, the disputes arisingon account of the implementation and interpretation of the Directive on the European level attract significance domestically. Consequently, the guidelines on correct interpretation of the Directive importing the practical, business-oriented solutions may well have application on European level. This underlines the exigency for a thorough analysis on the implications of the meaning and potential scope of Database protection in Finland and the European Union. This position hasto be contrasted with the larger, international sphere, which in early 2005 does differ markedly from European Union stance, directly having a negative effect on international trade particularly in digital content. A particular case in point is the USA, a database producer primus inter pares, not at least yet having aSui Generis database regime or its kin, while both the political and academic discourse on the matter abounds. 5. The objectives of the study The above mentioned background with its several open issues calls for the detailed study of thefollowing questions: -What is a database-at-law and when is a database protected by intellectual property rights, particularly by the European database regime?What is the international situation? -How is a database protected and what is its relation with other intellectual property regimes, particularly in the Digital context? -The opportunities and threats provided by current protection to creators, users and the society as a whole, including the commercial and cultural implications? -The difficult question on relation of the Database protection and protection of factual information as such. 6. Dsiposition The Study, in purporting to analyse and cast light on the questions above, is divided into three mainparts. The first part has the purpose of introducing the political and rationalbackground and subsequent legislative evolution path of the European database protection, reflected against the international backdrop on the issue. An introduction to databases, originally a vehicle of modern computing and information andcommunication technology, is also incorporated. The second part sets out the chosen and existing two-tier model of the database protection, reviewing both itscopyright and Sui Generis right facets in detail together with the emergent application of the machinery in real-life societal and particularly commercial context. Furthermore, a general outline of copyright, relevant in context of copyright databases is provided. For purposes of further comparison, a chapter on the precursor of Sui Generi, database right, the Nordic catalogue rule also ensues. The third and final part analyses the positive and negative impact of the database protection system and attempts to scrutinize the implications further in the future with some caveats and tentative recommendations, in particular as regards the convoluted issue concerning the IPR protection of information per se, a new tenet in the domain of copyright and related rights.

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Mechanistic soil-crop models have become indispensable tools to investigate the effect of management practices on the productivity or environmental impacts of arable crops. Ideally these models may claim to be universally applicable because they simulate the major processes governing the fate of inputs such as fertiliser nitrogen or pesticides. However, because they deal with complex systems and uncertain phenomena, site-specific calibration is usually a prerequisite to ensure their predictions are realistic. This statement implies that some experimental knowledge on the system to be simulated should be available prior to any modelling attempt, and raises a tremendous limitation to practical applications of models. Because the demand for more general simulation results is high, modellers have nevertheless taken the bold step of extrapolating a model tested within a limited sample of real conditions to a much larger domain. While methodological questions are often disregarded in this extrapolation process, they are specifically addressed in this paper, and in particular the issue of models a priori parameterisation. We thus implemented and tested a standard procedure to parameterize the soil components of a modified version of the CERES models. The procedure converts routinely-available soil properties into functional characteristics by means of pedo-transfer functions. The resulting predictions of soil water and nitrogen dynamics, as well as crop biomass, nitrogen content and leaf area index were compared to observations from trials conducted in five locations across Europe (southern Italy, northern Spain, northern France and northern Germany). In three cases, the model’s performance was judged acceptable when compared to experimental errors on the measurements, based on a test of the model’s root mean squared error (RMSE). Significant deviations between observations and model outputs were however noted in all sites, and could be ascribed to various model routines. In decreasing importance, these were: water balance, the turnover of soil organic matter, and crop N uptake. A better match to field observations could therefore be achieved by visually adjusting related parameters, such as field-capacity water content or the size of soil microbial biomass. As a result, model predictions fell within the measurement errors in all sites for most variables, and the model’s RMSE was within the range of published values for similar tests. We conclude that the proposed a priori method yields acceptable simulations with only a 50% probability, a figure which may be greatly increased through a posteriori calibration. Modellers should thus exercise caution when extrapolating their models to a large sample of pedo-climatic conditions for which they have only limited information.

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Occupational exposure modeling is widely used in the context of the E.U. regulation on the registration, evaluation, authorization, and restriction of chemicals (REACH). First tier tools, such as European Centre for Ecotoxicology and TOxicology of Chemicals (ECETOC) targeted risk assessment (TRA) or Stoffenmanager, are used to screen a wide range of substances. Those of concern are investigated further using second tier tools, e.g., Advanced REACH Tool (ART). Local sensitivity analysis (SA) methods are used here to determine dominant factors for three models commonly used within the REACH framework: ECETOC TRA v3, Stoffenmanager 4.5, and ART 1.5. Based on the results of the SA, the robustness of the models is assessed. For ECETOC, the process category (PROC) is the most important factor. A failure to identify the correct PROC has severe consequences for the exposure estimate. Stoffenmanager is the most balanced model and decision making uncertainties in one modifying factor are less severe in Stoffenmanager. ART requires a careful evaluation of the decisions in the source compartment since it constitutes ∼75% of the total exposure range, which corresponds to an exposure estimate of 20-22 orders of magnitude. Our results indicate that there is a trade off between accuracy and precision of the models. Previous studies suggested that ART may lead to more accurate results in well-documented exposure situations. However, the choice of the adequate model should ultimately be determined by the quality of the available exposure data: if the practitioner is uncertain concerning two or more decisions in the entry parameters, Stoffenmanager may be more robust than ART.

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The objective of this thesis is to find out how information and communication technology affects the global consumption of printing and writing papers. Another objective is to find out, whether there are differences between paper grades in these effects. The empirical analysis is conducted by linear regression analysis using three sets of country-level panel data from 1990-2006. Data set of newsprint contains 95 countries, data set of uncoated woodfree paper 61 countries and data set of coated mechanical paper 42 countries. The material is based on paper consumption data of RISI’s Industry Statistics Database and on the information and communication technology data of GMID-database. Results indicate that number of Internet users has statistically significant negative effect on the consumption of newsprint and on the consumption of coated mechanical paper and number of mobile telephone users has positive effect on the consumptions of these papers. Results also indicate that information and communication technologies have only small effect on consumption of uncoated woodfree paper or no significant effect at all, but these results are more uncertain to some extent.

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OBJECTIVES: The aim of the study was to statistically model the relative increased risk of cardiovascular disease (CVD) per year older in Data collection on Adverse events of anti-HIV Drugs (D:A:D) and to compare this with the relative increased risk of CVD per year older in general population risk equations. METHODS: We analysed three endpoints: myocardial infarction (MI), coronary heart disease (CHD: MI or invasive coronary procedure) and CVD (CHD or stroke). We fitted a number of parametric age effects, adjusting for known risk factors and antiretroviral therapy (ART) use. The best-fitting age effect was determined using the Akaike information criterion. We compared the ageing effect from D:A:D with that from the general population risk equations: the Framingham Heart Study, CUORE and ASSIGN risk scores. RESULTS: A total of 24 323 men were included in analyses. Crude MI, CHD and CVD event rates per 1000 person-years increased from 2.29, 3.11 and 3.65 in those aged 40-45 years to 6.53, 11.91 and 15.89 in those aged 60-65 years, respectively. The best-fitting models included inverse age for MI and age + age(2) for CHD and CVD. In D:A:D there was a slowly accelerating increased risk of CHD and CVD per year older, which appeared to be only modest yet was consistently raised compared with the risk in the general population. The relative risk of MI with age was not different between D:A:D and the general population. CONCLUSIONS: We found only limited evidence of accelerating increased risk of CVD with age in D:A:D compared with the general population. The absolute risk of CVD associated with HIV infection remains uncertain.

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Abstract Purpose: Several well-known managerial accounting performance measurement models rely on causal assumptions. Whilst users of the models express satisfaction and link them with improved organizational performance, academic research, of the realworld applications, shows few reliable statistical associations. This paper provides a discussion on the"problematic" of causality in a performance measurement setting. Design/methodology/approach: This is a conceptual study based on an analysis and synthesis of the literature from managerial accounting, organizational theory, strategic management and social scientific causal modelling. Findings: The analysis indicates that dynamic, complex and uncertain environments may challenge any reliance upon valid causal models. Due to cognitive limitations and judgmental biases, managers may fail to trace correct cause-and-effect understanding of the value creation in their organizations. However, even lacking this validity, causal models can support strategic learning and perform as organizational guides if they are able to mobilize managerial action. Research limitations/implications: Future research should highlight the characteristics necessary for elaboration of convincing and appealing causal models and the social process of their construction. Practical implications: Managers of organizations using causal models should be clear on the purposes of their particular models and their limitations. In particular, difficulties are observed in specifying detailed cause and effect relations and their potential for communicating and directing attention. They should therefore construct their models to suit the particular purpose envisaged. Originality/value: This paper provides an interdisciplinary and holistic view on the issue of causality in managerial accounting models.

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In this chapter, we examine the multiple dimensions of declarations of fertility in-tention in order to provide a critical reading of currently used indicators of the childbearing decision-making process. Using a qualitative approach, we pay atten-tion to the complexity of the process through which individuals make (or fail to make) plans regarding their reproductive future. The data are a series of compara-ble in-depth interviews conducted in a number of European countries with varying fertility levels, and differing normative and institutional contexts. First, we ana-lyze the meanings that respondents attribute to their childbearing intentions, pay-ing particular attention to uncertain intentions that are often underanalyzed. Se-cond, we study the ways in which individuals vary in holding to their intentions over time, and consider why they might change their minds, even over relatively short periods of time. Third, we examine how several aspects of the larger social context (attitudes towards having children, family policy, norms related to the di-vision of labor, norms about the timing of children) shape fertility intentions.

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Tuotekehityksestä ja sen johtamisesta on tullut erittäin tärkeä osa tietoliikenneteollisuutta. Jatkuva teknologinen kehitys ja lyhentyneet tuotteiden elinkaaret ovat saaneet yritykset panostamaan tuotekehitysprosesseihin ja johtamiseen. Erityisesti nopeatempoiset ja lyhytkestoiset projektit onkin koettu ongelmallisiksi. Diplomityön tavoitteena oli tutkia teoriassa uusien tuotteiden tuotekehitystä, tuotekehitysprosesseja sekä projektijohtamista. Käytännön osuudessa oli tavoitteena kehittää kokeellinen tuotekehitysmalli nopeatempoisten ja lyhytkestoisten tuotekehitysprojektien tarpeisiin muuttuvissa ja epävarmoissa olosuhteissa. Tavoitteena oli myös käyttää ja analysoida kehitettyä kokeellista tuotekehitysmallia lyhytkestoisen tuotekehitysprojektin yhteydessä. Työn tuloksena saatiin ohjelmistotuote vaadituilla ominaisuuksilla vaaditussa ajassa ja todettiin projektissa käytetyn kokeellisen tuotekehitysmallin osoittautuneen toimivaksi. Jatkotutkimuksia tarvitaan selvittämään mallin sopivuutta ja sen kehityskohteita erilaisten tuotekehitysprojektien kohdalla.