Rigid body dynamics and Kalman filtering

X-ray computed log tomography has always been applied for qualitative reconstructions. In most cases, a series of consecutive slices of the timber are scanned to estimate the 3D image reconstruction of the entire log. However, the unexpected movement of the timber under study influences the quality of image reconstruction since the position and orientation of some scanned slices can be incorrectly estimated. In addition, the reconstruction time remains a significant challenge for practical applications. The present study investigates the possibility to employ modern physics engines for the problem of estimating the position of a moving rigid body and its scanned slices which are subject to X-ray computed tomography. The current work includes implementations of the extended Kalman filter and an algebraic reconstruction method for fan-bean computer tomography. In addition, modern techniques such as NVidia PhysX and CUDA are used in current study. As the result, it is numerically shown that it is possible to apply the extended Kalman filter together with a real-time physics engine, known as PhysX, in order to determine the position of a moving object. It is shown that the position of the rigid body can be determined based only on reconstructions of its slices. However, the simulation of the body movement sometimes is subject to an error during Kalman filter employment as PhysX is not always able to continue simulating the movement properly because of incorrect state estimation.

Studies of rotor dynamics using a multibody simulation approach

The non-idealities in a rotor-bearing system may cause undesirable subcritical superharmonic resonances that occur when the rotating speed of the rotor is a fraction of the natural frequency of the system. These resonances arise partly from the non-idealities of the bearings. This study introduces a novel simulation approach that can be used to study the superharmonic vibrations of rotor-bearing systems. The superharmonic vibrations of complex rotor-bearing systems can be studied in an accurate manner by combining a detailed rotor and bearing model in a multibody simulation approach. The research looks at the theoretical background of multibody formulations that can be used in the dynamic analysis of flexible rotors. The multibody formulations currently in use are suitable for linear deformation analysis only. However, nonlinear formulation may arise in high-speed rotor dynamics applications due to the cenrrifugal stiffening effect. For this reason, finite element formulations that can describe nonlinear deformation are also introduced in this work. The description of the elastic forces in the absolute nodal coordinate formulation is studied and improved. A ball bearing model that includes localized and distributed defects is developed in this study. This bearing model could be used in rotor dynamics or multibody code as an interface elements between the rotor and the supporting structure. The model includes descriptions of the nonlinear Hertzian contact deformation and the elastohydrodynamic fluid film. The simulation approaches and models developed here are applied in the analysis of two example rotor-bearing systems. The first example is an electric motor supported by two ball bearings and the second is a roller test rig that consists of the tube roll of a paper machine supported by a hard-bearing-type balanceing machine. The simulation results are compared to the results available in literature as well as to those obtained by measuring the existing structure. In both practical examples, the comparison shows that the simulation model is capable of predicting the realistic responses of a rotor system. The simulation approaches developed in this work can be used in the analysis of the superharmonic vibrations of general rotor-bearing systems.

Trust Embedded Open Innovation: Human-Centricity in the Financial

Globalization and interconnectedness in the worldwide sphere have changed the existing and prevailing modus operandi of organizations around the globe and have challenged existing practices along with the business as usual mindset. There are no rules in terms of creating a competitive advantage and positioning within an unstable, constantly changing and volatile globalized business environment. The financial industry, the locomotive or the flagship industry of global economy, especially, within the aftermath of the financial crisis, has reached a certain point trying to recover and redefine its strategic orientation and positioning within the global business arena. Innovation has always been a trend and a buzzword and by many has been considered as the ultimate answer to any kind of problem. The mantra Innovate or Die has been prevailing in any organizational entity in a, sometimes, ruthless endeavour to develop cutting-edge products and services and capture a landmark position in the market. The emerging shift from a closed to an open innovation paradigm has been considered as new operational mechanism within the management and leadership of the company of the future. To that respect, open innovation has been experiencing a tremendous growth research trajectory by putting forward a new way of exchanging and using surplus knowledge in order to sustain innovation within organizations and in the level of industry. In the abovementioned reality, there seems to be something missing: the human element. This research, by going beyond the traditional narratives for open innovation, aims at making an innovative theoretical and managerial contribution developed and grounded on the on-going discussion regarding the individual and organizational barriers to open innovation within the financial industry. By functioning across disciplines and researching out to primary data, it debunks the myth that open innovation is solely a knowledge inflow and outflow mechanism and sheds light to the understanding on the why and the how organizational open innovation works by enlightening the broader dynamics and underlying principles of this fascinating paradigm. Little attention has been given to the role of the human element, the foundational pre-requisite of trust encapsulated within the precise and fundamental nature of organizing for open innovation, the organizational capabilities, the individual profiles of open innovation leaders, the definition of open innovation in the realms of the financial industry, the strategic intent of the financial industry and the need for nurturing a societal impact for human development. To that respect, this research introduces the trust-embedded approach to open innovation as a new insightful way of organizing for open innovation. It unveils the peculiarities of the corporate and individual spheres that act as a catalyst towards the creation of productive open innovation activities. The incentive of this research captures the fundamental question revolving around the need for financial institutions to recognise the importance for organizing for open innovation. The overarching question is why and how to create a corporate culture of openness in the financial industry, an organizational environment that can help open innovation excel. This research shares novel and cutting edge outcomes and propositions both under the prism of theory and practice. The trust-embedded open innovation paradigm captures the norms and narratives around the way of leading open innovation within the 21st century by cultivating a human-centricity mindset that leads to the creation of human organizations, leaving behind the dehumanization mindset currently prevailing within the financial industry.

Models to study intermediate filament dynamics and functions

Intermediate filaments are part of the cytoskeleton and nucleoskeleton; they provide cells with structure and have important roles in cell signalling. The IFs are a large protein family with more than 70 members; each tightly regulated and expressed in a cell type-specific manner. Although the IFs have been known and studied for decades, our knowledge about their specific functions is still limited, despite the fact that mutations in IF genes cause numerous severe human diseases. In this work, three IF proteins are examined more closely; the nuclear lamin A/C and the cytoplasmic nestin and vimentin. In particular the regulation of lamin A/C dynamics, the role of nestin in muscle and body homeostasis as well as the functions and evolutionary aspects of vimentin are investigated. Together this data highlights some less well understood functions of these IFs. We used mass-spectrometry to identify inter-phase specific phosphorylation sites on lamin A. With the use of genetically engineered lamin A protein in combination with high resolution microscopy and biochemical methods we discovered novel roles for this phosphorylation in regulation of lamin dynamics. More specifically, our data suggests that the phosphorylation of certain amino acids in lamin A determines the localization and dynamics of the protein. In addition, we present results demonstrating that lamin A regulates Cdk5-activity. In the second study we use mice lacking nestin to gain more knowledge of this seldom studied protein. Our results show that nestin is essential for muscle regeneration; mice lacking nestin recover more slowly from muscle injury and show signs of spontaneous muscle regeneration, indicating that their muscles are more sensitive to stresses and injury. The absence of nestin also leads to decreased over-all muscle mass and slower body growth. Furthermore, nestin has a role in controlling testicle homeostasis as nestin-/- male mice show a greater variation in testicle size. The common fruit fly Drosophila melanogaster lacks cytoplasmic IFs as most insects do. By creating a fly that expresses human vimentin we establish a new research platform for vimentin studies, as well as provide a new tool for the studies of IF evolution.

Computational Market Dynamics of Virtual Economies

The last two decades have provided a vast opportunity to live and explore the compulsive imaginary world or virtual world through massively multiplayer online role-playing games (MMORPGs). MMORPG gives a wide range of opportunities to its users to participate with multi-players on the same platform, to communicate and to do real time actions. There is a virtual economy in these games which is largely player-driven. In-game currency provides its users to build up their Avatars, to buy or sell the necessary goods to play, survive in the games and so on. As a part of virtual economies generated through EVE Online, this thesis mainly focuses on how the prices of the minerals in EVE Online behave by applying the Jabłonska- Capasso-Morale (JCM) mathematical simulation model. It is to verify up to what degree the model can reproduce the virtual economy behavior. The model is applied to buy and sell prices of two minerals namely, isogen and morphite. The simulation results demonstrate that JCM model ts reasonably well to the mineral prices, which lets us conclude that virtual economies behave similarly to the real ones.

Future operational-tactical level warfare : challenges and opportunities for the defence of Finland

Finnish Defence Studies is published under the auspices of the National Defence College, and the contributions reflect the fields of research and teaching of the College. Finnish Defence Studies will occasionally feature documentation on Finnish Security Policy. Views expressed are those of the authors and do not necessarily imply endorsement by the National Defence College.

Individual Crimes or a Sociological Phenomenon: A Critical discourse analysis of the 2014 Royal Canadian Mounted Police National Operational Overview on missing and murdered Indigenous women in Canada

Pro gradu -tutkielma käsittelee Kanadan poliisivoimien, Royal Canadian Mounted Police (RCMP), vuoden 2014 operationaalista raporttia Kanadan kadonneista ja murhatuista alkuperäiskansojen naisista. Heitä katoaa ja murhataan Kanadassa suhteessa huomattavasti enemmän kuin muita naisia. Aihe on hyvin ajankohtainen sekä kriittinen ja siihen on paikallisten organisaatioiden lisäksi kiinnittänyt huomiota mm. Amnesty International ja Yhdistyneet Kansakunnat. Tilannetta pidetään jo ihmisoikeuskriisinä ja sen puolesta puhuminen voidaan nähdä osana laajempaa kansannousua alkuperäiskansojen oikeuksien puolesta. Kanadan hallitusta sekä poliisivoimia on syytetty välinpitämättömyydestä ja rasismista, poliiseja jopa väkivallasta alkuperäiskansojen naisia kohtaan. Kanadan hallitus ei myönnä ongelman olevan sosiologinen ilmiö, vaan pääministerin mukaan naisten katoamiset ja murhat ovat yksittäisiä rikoksia. Tilanteen taustalla on laajempi ongelma, joka juontaa juurensa kolonialismista, alkuperäiskansojen pakkokoulutuksesta ja heidän kulttuurinsa sekä identiteettinsä tuhoamisesta. Ennakkoluulot ja stereotypiat elävät yhä vahvana luoden heikon aseman alkuperäiskansojen edustajille ja tässä tapauksessa erityisesti naisille, joita myös usein syytetään omista ongelmistaan. Tutkielma selvittää, onko tämä operationaalinen raportti eriarvoisuutta, stereotypioita sekä ennakkoluuloja ylläpitävä ja tukeeko se näkemystä sosiologisesta ilmiöstä. Poliisivoimat ovat yhteiskunnassa vaikutusvaltaisessa asemassa ja voivat edesauttaa, jatkaa ja voimistaa syrjivää ajattelua, käytöstä ja viestintää. Vaikka he myös ajavat alkuperäiskansojen etuja, tulee heidän toimintaansa ja täten tätä kyseistä raporttia tarkastella kriittisesti. Tutkielma keskittyy kriittiseen diskurssianalyysiin (Fairclough 1995, Wodak & Meyer 2009). Raportin teksti ei ole avoimesti diskriminoivaa ja keskittyy tilastojen ja lukujen raportointiin sekä vertailuun, luoden samalla kuvan asianomaisista sekä tilanteesta yleisesti. Makroanalyysi (van Dijk 1977, 1980) mahdollistaa korkeamman tason ajatusten ja ideoiden esille tuonnin paljastaen ns. rivien välistä löytyvän viestinnän. Näistä makroanalyysin tuloksista etsitään erilaisia diskurssistrategioita (Reisigl & Wodak 2001), joiden avulla luodaan mm. kuva positiivisesta itsestä ja negatiivisesta toisesta. Näitä tuloksia tuetaan lyhyellä multimodaalisella analyysillä, joka keskittyy lähinnä raportin kahteen kuvaan (Kress & van Leeuwen 2006). Lopuksi tuloksista keskustellaan suhteessa yhteiskunnan valtasuhteisiin (Foucault 1976), rasismiin ja seksismiin. Analyysin perusteella raportti on selkeästi diskriminoiva. Se tuo esiin vanhoja stereotypioita ja ennakkoluuloja, esittää tilanteen alkuperäiskansojen sisäisenä ongelmana, jättää mainitsematta tilanteen taustat ja luo hyvin positiivisen kuvan poliisivoimista (RCMP). Tällä tavoin se ylläpitää yhteiskunnan epätasapainoisia valtasuhteita ja alkuperäiskansojen naisten heikompaa ja marginalisoitua asemaa. Raportti todistaa kuinka syvällä Kanadan yhteiskunnassa jopa institutionaalisella tasolla nämä ajatukset piilevät, sillä diskriminaatio ulottuu tapausten syistä niiden käsittelyyn ja raportointiin. Tilanne on huolestuttava ja voidaan nähdä sosiologisena ilmiönä. Poliisivoimien tulisi lisätä sisäistä koulutusta asian suhteen sekä hallituksen tutkia tätä ilmiönä ja paneutua sen selvittämiseen laaja-alaisesti ja läpinäkyvästi.

Individual Crimes or a Sociological Phenomenon: A Critical discourse analysis of the 2014 Royal Canadian Mounted Police National Operational Overview on missing and murdered Indigenous women in Canada

Pro gradu -tutkielma käsittelee Kanadan poliisivoimien, Royal Canadian Mounted Police (RCMP), vuoden 2014 operationaalista raporttia Kanadan kadonneista ja murhatuista alkuperäiskansojen naisista. Heitä katoaa ja murhataan Kanadassa suhteessa huomattavasti enemmän kuin muita naisia. Aihe on hyvin ajankohtainen sekä kriittinen ja siihen on paikallisten organisaatioiden lisäksi kiinnittänyt huomiota mm. Amnesty International ja Yhdistyneet Kansakunnat. Tilannetta pidetään jo ihmisoikeuskriisinä ja sen puolesta puhuminen voidaan nähdä osana laajempaa kansannousua alkuperäiskansojen oikeuksien puolesta. Kanadan hallitusta sekä poliisivoimia on syytetty välinpitämättömyydestä ja rasismista, poliiseja jopa väkivallasta alkuperäiskansojen naisia kohtaan. Kanadan hallitus ei myönnä ongelman olevan sosiologinen ilmiö, vaan pääministerin mukaan naisten katoamiset ja murhat ovat yksittäisiä rikoksia. Tilanteen taustalla on laajempi ongelma, joka juontaa juurensa kolonialismista, alkuperäiskansojen pakkokoulutuksesta ja heidän kulttuurinsa sekä identiteettinsä tuhoamisesta. Ennakkoluulot ja stereotypiat elävät yhä vahvana luoden heikon aseman alkuperäiskansojen edustajille ja tässä tapauksessa erityisesti naisille, joita myös usein syytetään omista ongelmistaan. Tutkielma selvittää, onko tämä operationaalinen raportti eriarvoisuutta, stereotypioita sekä ennakkoluuloja ylläpitävä ja tukeeko se näkemystä sosiologisesta ilmiöstä. Poliisivoimat ovat yhteiskunnassa vaikutusvaltaisessa asemassa ja voivat edesauttaa, jatkaa ja voimistaa syrjivää ajattelua, käytöstä ja viestintää. Vaikka he myös ajavat alkuperäiskansojen etuja, tulee heidän toimintaansa ja täten tätä kyseistä raporttia tarkastella kriittisesti. Tutkielma keskittyy kriittiseen diskurssianalyysiin (Fairclough 1995, Wodak & Meyer 2009). Raportin teksti ei ole avoimesti diskriminoivaa ja keskittyy tilastojen ja lukujen raportointiin sekä vertailuun, luoden samalla kuvan asianomaisista sekä tilanteesta yleisesti. Makroanalyysi (van Dijk 1977, 1980) mahdollistaa korkeamman tason ajatusten ja ideoiden esille tuonnin paljastaen ns. rivien välistä löytyvän viestinnän. Näistä makroanalyysin tuloksista etsitään erilaisia diskurssistrategioita (Reisigl & Wodak 2001), joiden avulla luodaan mm. kuva positiivisesta itsestä ja negatiivisesta toisesta. Näitä tuloksia tuetaan lyhyellä multimodaalisella analyysillä, joka keskittyy lähinnä raportin kahteen kuvaan (Kress & van Leeuwen 2006). Lopuksi tuloksista keskustellaan suhteessa yhteiskunnan valtasuhteisiin (Foucault 1976), rasismiin ja seksismiin. Analyysin perusteella raportti on selkeästi diskriminoiva. Se tuo esiin vanhoja stereotypioita ja ennakkoluuloja, esittää tilanteen alkuperäiskansojen sisäisenä ongelmana, jättää mainitsematta tilanteen taustat ja luo hyvin positiivisen kuvan poliisivoimista (RCMP). Tällä tavoin se ylläpitää yhteiskunnan epätasapainoisia valtasuhteita ja alkuperäiskansojen naisten heikompaa ja marginalisoitua asemaa. Raportti todistaa kuinka syvällä Kanadan yhteiskunnassa jopa institutionaalisella tasolla nämä ajatukset piilevät, sillä diskriminaatio ulottuu tapausten syistä niiden käsittelyyn ja raportointiin. Tilanne on huolestuttava ja voidaan nähdä sosiologisena ilmiönä. Poliisivoimien tulisi lisätä sisäistä koulutusta asian suhteen sekä hallituksen tutkia tätä ilmiönä ja paneutua sen selvittämiseen laaja-alaisesti ja läpinäkyvästi.

Public-private partnership investments in dry ports – Russian logistics markets and risks

The investments have always been considered as an essential backbone and so-called ‘locomotive’ for the competitive economies. However, in various countries, the state has been put under tight budget constraints for the investments in capital intensive projects. In response to this situation, the cooperation between public and private sector has grown based on public-private mechanism. The promotion of favorable arrangement for collaboration between public and private sectors for the provision of policies, services, and infrastructure in Russia can help to address the problems of dry ports development that neither municipalities nor the private sector can solve alone. Especially, the stimulation of public-private collaboration is significant under the exposure to externalities that affect the magnitude of the risks during all phases of project realization. In these circumstances, the risk in the projects also is becoming increasingly a part of joint research and risk management practice, which is viewed as a key approach, aiming to take active actions on existing global and specific factors of uncertainties. Meanwhile, a relatively little progress has been made on the inclusion of the resilience aspects into the planning process of a dry ports construction that would instruct the capacity planner, on how to mitigate the occurrence of disruptions that may lead to million dollars of losses due to the deviation of the future cash flows from the expected financial flows on the project. The current experience shows that the existing methodological base is developed fragmentary within separate steps of supply chain risk management (SCRM) processes: risk identification, risk evaluation, risk mitigation, risk monitoring and control phases. The lack of the systematic approach hinders the solution of the problem of risk management processes of dry port implementation. Therefore, management of various risks during the investments phases of dry port projects still presents a considerable challenge from the practical and theoretical points of view. In this regard, the given research became a logical continuation of fundamental research, existing in the financial models and theories (e.g., capital asset pricing model and real option theory), as well as provided a complementation for the portfolio theory. The goal of the current study is in the design of methods and models for the facilitation of dry port implementation through the mechanism of public-private partnership on the national market that implies the necessity to mitigate, first and foremost, the shortage of the investments and consequences of risks. The problem of the research was formulated on the ground of the identified contradictions. They rose as a continuation of the trade-off between the opportunities that the investors can gain from the development of terminal business in Russia (i.e. dry port implementation) and risks. As a rule, the higher the investment risk, the greater should be their expected return. However, investors have a different tolerance for the risks. That is why it would be advisable to find an optimum investment. In the given study, the optimum relates to the search for the efficient portfolio, which can provide satisfaction to the investor, depending on its degree of risk aversion. There are many theories and methods in finance, concerning investment choices. Nevertheless, the appropriateness and effectiveness of particular methods should be considered with the allowance of the specifics of the investment projects. For example, the investments in dry ports imply not only the lump sum of financial inflows, but also the long-term payback periods. As a result, capital intensity and longevity of their construction determine the necessity from investors to ensure the return on investment (profitability), along with the rapid return on investment (liquidity), without precluding the fact that the stochastic nature of the project environment is hardly described by the formula-based approach. The current theoretical base for the economic appraisals of the dry port projects more often perceives net present value (NPV) as a technique superior to other decision-making criteria. For example, the portfolio theory, which considers different risk preference of an investor and structures of utility, defines net present value as a better criterion of project appraisal than discounted payback period (DPP). Meanwhile, in business practice, the DPP is more popular. Knowing that the NPV is based on the assumptions of certainty of project life, it cannot be an accurate appraisal approach alone to determine whether or not the project should be accepted for the approval in the environment that is not without of uncertainties. In order to reflect the period or the project’s useful life that is exposed to risks due to changes in political, operational, and financial factors, the second capital budgeting criterion – discounted payback period is profoundly important, particularly for the Russian environment. Those statements represent contradictions that exist in the theory and practice of the applied science. Therefore, it would be desirable to relax the assumptions of portfolio theory and regard DPP as not fewer relevant appraisal approach for the assessment of the investment and risk measure. At the same time, the rationality of the use of both project performance criteria depends on the methods and models, with the help of which these appraisal approaches are calculated in feasibility studies. The deterministic methods cannot ensure the required precision of the results, while the stochastic models guarantee the sufficient level of the accuracy and reliability of the obtained results, providing that the risks are properly identified, evaluated, and mitigated. Otherwise, the project performance indicators may not be confirmed during the phase of project realization. For instance, the economic and political instability can result in the undoing of hard-earned gains, leading to the need for the attraction of the additional finances for the project. The sources of the alternative investments, as well as supportive mitigation strategies, can be studied during the initial phases of project development. During this period, the effectiveness of the investments undertakings can also be improved by the inclusion of the various investors, e.g. Russian Railways’ enterprises and other private companies in the dry port projects. However, the evaluation of the effectiveness of the participation of different investors in the project lack the methods and models that would permit doing the particular feasibility study, foreseeing the quantitative characteristics of risks and their mitigation strategies, which can meet the tolerance of the investors to the risks. For this reason, the research proposes a combination of Monte Carlo method, discounted cash flow technique, the theory of real options, and portfolio theory via a system dynamics simulation approach. The use of this methodology allows for comprehensive risk management process of dry port development to cover all aspects of risk identification, risk evaluation, risk mitigation, risk monitoring, and control phases. A designed system dynamics model can be recommended for the decision-makers on the dry port projects that are financed via a public-private partnership. It permits investors to make a decision appraisal based on random variables of net present value and discounted payback period, depending on different risks factors, e.g. revenue risks, land acquisition risks, traffic volume risks, construction hazards, and political risks. In this case, the statistical mean is used for the explication of the expected value of the DPP and NPV; the standard deviation is proposed as a characteristic of risks, while the elasticity coefficient is applied for rating of risks. Additionally, the risk of failure of project investments and guaranteed recoupment of capital investment can be considered with the help of the model. On the whole, the application of these modern methods of simulation creates preconditions for the controlling of the process of dry port development, i.e. making managerial changes and identifying the most stable parameters that contribute to the optimal alternative scenarios of the project realization in the uncertain environment. System dynamics model allows analyzing the interactions in the most complex mechanism of risk management process of the dry ports development and making proposals for the improvement of the effectiveness of the investments via an estimation of different risk management strategies. For the comparison and ranking of these alternatives in their order of preference to the investor, the proposed indicators of the efficiency of the investments, concerning the NPV, DPP, and coefficient of variation, can be used. Thus, rational investors, who averse to taking increased risks unless they are compensated by the commensurate increase in the expected utility of a risky prospect of dry port development, can be guided by the deduced marginal utility of investments. It is computed on the ground of the results from the system dynamics model. In conclusion, the outlined theoretical and practical implications for the management of risks, which are the key characteristics of public-private partnerships, can help analysts and planning managers in budget decision-making, substantially alleviating the effect from various risks and avoiding unnecessary cost overruns in dry port projects.

Parameter estimation for Chaotic or Stochastic Dynamics

Since its discovery, chaos has been a very interesting and challenging topic of research. Many great minds spent their entire lives trying to give some rules to it. Nowadays, thanks to the research of last century and the advent of computers, it is possible to predict chaotic phenomena of nature for a certain limited amount of time. The aim of this study is to present a recently discovered method for the parameter estimation of the chaotic dynamical system models via the correlation integral likelihood, and give some hints for a more optimized use of it, together with a possible application to the industry. The main part of our study concerned two chaotic attractors whose general behaviour is diff erent, in order to capture eventual di fferences in the results. In the various simulations that we performed, the initial conditions have been changed in a quite exhaustive way. The results obtained show that, under certain conditions, this method works very well in all the case. In particular, it came out that the most important aspect is to be very careful while creating the training set and the empirical likelihood, since a lack of information in this part of the procedure leads to low quality results.

Stochastic particle models: mean reversion and burgers dynamics. An application to commodity markets

The aim of this study is to propose a stochastic model for commodity markets linked with the Burgers equation from fluid dynamics. We construct a stochastic particles method for commodity markets, in which particles represent market participants. A discontinuity in the model is included through an interacting kernel equal to the Heaviside function and its link with the Burgers equation is given. The Burgers equation and the connection of this model with stochastic differential equations are also studied. Further, based on the law of large numbers, we prove the convergence, for large N, of a system of stochastic differential equations describing the evolution of the prices of N traders to a deterministic partial differential equation of Burgers type. Numerical experiments highlight the success of the new proposal in modeling some commodity markets, and this is confirmed by the ability of the model to reproduce price spikes when their effects occur in a sufficiently long period of time.

Geographical Studies of Underwater Light Dynamics in the Coastal Archipelago of SW Finland, Baltic Sea

The underwater light field is an important environmental variable as it, among other things, enables aquatic primary production. Although the portion of solar radiation that is referred to as visible light penetrates water, it is restricted to a limited surface water layer because of efficient absorption and scattering processes. Based on the varying content of optical constituents in the water, the efficiency of light attenuation changes in many dimensions and over various spatial and temporal scales. This thesis discusses the underwater light dynamics of a transitional coastal archipelago in south-western Finland, in the Baltic Sea. While the area has long been known to have a highly variable underwater light field, quantified knowledge on the phenomenon has been scarce, patchy, or non-existent. This thesis focuses on the variability in the underwater light field through euphotic depths (1% irradiance remaining), which were derived from in situ measurements of vertical profiles of photosynthetically active radiation (PAR). Spot samples were conducted in the archipelago of south-western Finland, mainly during the ice-free growing seasons of 2010 and 2011. In addition to quantifying both the seasonal and geographical patterns of euphotic depth development, the need and usability of underwater light information are also discussed. Light availability was found to fluctuate in multiple dimensions and scales. The euphotic depth was shown to have combined spatio-temporal dynamics rather than separate changes in spatial and temporal dimensions. Such complexity in the underwater light field creates challenges in data collection, as well as in its utilisation. Although local information is needed, in highly variable conditions spot sampled information may only poorly represent its surroundings. Moreover, either temporally or spatially limited sampling may cause biases in understanding underwater light dynamics. Consequently, the application of light availability data, for example in ecological modelling, should be made with great caution.

Dynamics AX -toiminnanohjausjärjestelmän jatkuvuudenhallinta ja toipumissuunnitelma - Simulaatiotestausmalli: case CGI Suomi Oy

Nyky-yhteiskunta nojautuu vahvasti tietojärjestelmiin luoden laajemman arkkitehtuurisen kokonaisuuden, kybertoimintaympäristön. Liiketoimintaa tukevat tietojärjestelmät tukevat myös organisaatioiden prosesseja kokonaisvaltaisesti. Jotta näitä tärkeitä kyberympäristön tietojärjestelmä- sekä liiketoimintaympäristöresursseja pystytään käyttämään, tulee järjestelmien olla luotettavia ja sovellusten saatavilla vuorokauden ympäri tai aina tarvittaessa. Tilanteet, joissa järjestelmän käytettävyys vaarantuu, voivat eskaloitua yllättäen suuremmiksi, jos poikkeustilanteisiin ei ole varauduttu. Poikkeustilanteisiin varautumiseen tarvitaan jatkuvuudenhallintaa, joka on kiinteästi osa kattavampaa IT-strategiaa ja koko yhteiskunta-/yrityskulttuuria. Työ on toteutettu yhdistäen empiriaa ja teoriaa eli tavoitteena on teoreettisen tietämyksen ja käytännön kokemuksellisen oppimisen ja tietämyksen kautta luoda konstruktiivisella otteella toipumissuunnitelman testauksessa käytettävä simulaatiotestausmalli. Dynamics AX -toiminnanohjausjärjestelmän toipumissuunnitelman simulaatiotestausmallista rakentui selkeä ja kevyt työkalu asiakasyritysten toipumissuunnitelman simulaatiotestauksiin. Diplomityössä kuvatuilla keinotekoisilla järjestelmän häiriötilanteilla pystytään simuloimaan Dynamics AX:n toipumissuunnitelman testauksissa oikeita häiriötilanteita suhteellisen kattavalla tasolla.