Sahayrityksen laajentamisen kannattavuus

Diplomityön tavoitteena oli selvittää sahayrityksen tuotantokapasiteetin laajentamisen taloudellisia edellytyksiä, rajoitteita ja seurauksia. Teoriaosassa määritellään ensimmäiseksi kasvukykyinen yritys, joka on kannattava, maksuvelvoitteista suoriutuva ja vakavarainen. Toiseksi analysoidaan, kuinka tuotantovolyymin kasvattaminen näkyy sahan taseessa käyttöomaisuuden ja käyttöpääoman kasvuna. Kolmanneksi tarkastellaan vieraan pääoman tarvetta ja pääomakustannusten vaikutusta kapasiteettilaajennuksen kannattavuuteen.Neljänneksi tarkastellaan tuotantokapasiteetin laajentamisen kannattavuutta, kun käyttöomaisuutta hankitaan vuokraamalla tai toimintoja ulkoistetaan. Teoriaosan lopuksi määritellään periaatteet, kuinka nopeasti yritys voi kasvattaa liiketoimintaa vaarantamatta maksuvalmiutta, vakavaraisuutta ja kannattavuutta. Empiriaosassa tutkitaan 22 suomalaisen sahan tillinpäätöstietoja vuodelta 2003 ja kuvataan, miten erot kokoluokassa vaikuttavat sahojen kustannus- ja taserakenteeseen.Taseen osalta mittakaavaetua ei ollut havaittavissa. Tuloslaskelman osalta mittakaavaetua saavutettiin henkilökulujen osalta sahoilla, joiden liikevaihto asettui välille 15 - 25 Meur. Muilta osin pääoma- ja kustannuserät joko kasvoivat vakioisesti tai vaihtelivat satunnaisesti. Maksuvalmius perustui sahatoimialalla pääasiassa ostovelkojen ja muun lyhytaikaisen vieraan pääoman käyttöön.

Innovation Process Management and System Modelling

Työn tavoitteena oli perehtyä innovaatiojohtamisen ja järjestelmän soveltamiseen prosessiteollisuuden toimintaympäristöön. Kirjallisuuslähteitä apuna käyttäen perehdyttiin liiketoimintaympäristön innovaatiojohtamiselle asettamiin vaatimuksiin ja erilaisiin innovaatiojärjestelmiin. Olennaisena osana innovaatiojohtamiseen liittyy sidosryhmien tarpeiden ja niiden tarjoamien resurssien huomioiminen toiminnassa. Myöskin tuotekehityksen menetelmät ja työkalut ovat omalta osaltaan merkittävässä asemassa toiminnan tehokkuutta arvioitaessa. Innovaatiojärjestelmä tulee sopeuttaa yrityksen toimintoihin ja sen erityispiirteet huomioonottaen siten, että toiminnan johtaminen prosessina tuo yritykselle ja sen sidosryhmille lisäarvoa. Innovaatiojärjestelmän luominen yritykselle on ainayksilöllinen prosessi ja siihen ei ole olemassa yleispätevää menetelmää, joka voitaisiin ottaa käyttöön sellaisenaan. Yritys, jonka liiketoiminta keskittyy kuitupohjaisten pakkausmateriaalien valmistamiseen, joutuu täyttämään toiminnassaan materiaalintoimittajien, omien tuotantoprosessiensa ja asiakkaiden sekä jopa loppukäyttäjien uusille tuotteille luomat odotukset. Innovaatiojohtamista sävyttää toiminnan tulosten suuri epävarmuus ja sen vaativien aineellisten ja henkisten resurssien mittavuus. Innovaatiotoiminnan johtaminen prosessina, käyttäen hyväksi järjestelmämallia, tavoittelee systemaattista ja asetettujen kriteerien täyttämää lähestymistapaa tuotekehityksen ja uusien liiketoimintainnovaatioiden alueella. Kehitetyn mallin tulee palvella monimutkaista liiketoimintaympäristöä, jokatoisaalta perustuu tehokkaaseen massatuotantoon ja toisaalta pyrkii erilaistumaan palvelemalla sekä huomioimalla asiakkaidensa tuotteille asettamat vaatimukset.

Analysis of Active Magnet Bearing Control Software

Problems of the designing active magnet bearingcontrol are developed. The estimation controller are designed and applied to a rigid rotor. The mathematical model of the active magnet bearing controller is developed. This mathematical model is realized on a DSP. The results of this realization are analyzed. The conclusions about the digital signal processing are made.

Dynamic Capabilities and Firm Performance

Firms operating in a changing environment have a need for structures and practices that provide flexibility and enable rapid response to changes. Given the challenges they face in attempts to keep up with market needs, they have to continuously improve their processes and products, and develop new products to match market requirements. Success in changing markets depends on the firm's ability to convert knowledge into innovations, and consequently their internal structures and capabilities have an important role in innovation activities. According 10 the dynamic capability view of the firm, firms thus need dynamic capabilities in (he form ofassets, processes and structures that enable strategic flexibility and support entrepreneurial opportunity sensing and exploitation. Dynamic capabilities are also needed in conditions of rapid change in the operating environment, and in activities such as new product development and expansion to new markets. Despite the growing interest in these issues and the theoretical developments in the field of strategy research, there are still only very few empirical studies, and large-scale empirical studies in particular, that provide evidence that firms'dynamic capabilities are reflected in performance differences. This thesis represents an attempt to advance the research by providing empirical evidence of thelinkages between the firm's dynamic capabilities and performance in intenationalization and innovation activities. The aim is thus to increase knowledge and enhance understanding of the organizational factors that explain interfirm performance differences. The study is in two parts. The first part is the introduction and the second part comprises five research publications covering the theoretical foundations of the dynamic capability view and subsequent empirical analyses. Quantitative research methodology is used throughout. The thesis contributes to the literature in several ways. While a lot of prior research on dynamic capabilities is conceptual in nature, or conducted through case studies, this thesis introduces empirical measures for assessing the different aspects, and uses large-scale sampling to investigate the relationships between them and performance indicators. The dynamic capability view is further developed by integrating theoretical frameworks and research traditions from several disciplines. The results of the study provide support for the basic tenets of the dynamic capability view. The empirical findings demonstrate that the firm's ability to renew its knowledge base and other intangible assets, its proactive, entrepreneurial behavior, and the structures and practices that support operational flexibility arepositively related to performance indicators.

Ship Leases under IAS 17, case Fortum Shipping

International accounting standards will be applied from the1st of January 2005 in accounting of member states of the EU with a view of harmonizing the accounting practices in Europe, and on the long term even more widely. The purpose of adopting IAS accounting standards is to make the financial statements and financial information received from companies more comparable and more transparent for investors and other interest groups. IAS 17 introduces the treatment of a lease agreement in the light of the new accounting standards. Finnish companies have used finance leases widely as an alternative, off-balance sheet form of financing capital investments consistently with Finnish GAAP. Along with the appliance of IAS 17 the off-balance-sheet financing possibility of leases classified as finance leases will no longer exist. IAS 17 states that finance leases are going to be recognized in the balance sheet as both assets, in form of fixed assets, and loans in liabilities classified as long and short term loans. IAS 17 will make two major changes to the income statement. Firstly, the lease payments formerly treated as variable costs are moved below the operating profit level to finance costs. Secondly, the depreciations from the leased assets are also introduced. The effects to the case company's, Fortum Shipping's, income statement and balance sheet are remarkable. Along with the appliance of IAS Fortum Shipping's net assets are somewhat going to be doubled, the amount of liabilities increases significantly and the earnings before interests and taxes increases moderately. The preceding factors have a big effect on the case company's financial key figures. So, the IAS originated effects on balance sheet and income statement have essential impacts on a company's key financial indicators. Most significant changes can be found in key ratios measuring profitability, capital structure, and efficiency. This means that when comparing the IAS calculated profits of companies with the profits calculated prior with Finnish GAAP, the analysis should be made with prudence because the figures are not comparable on straight-forward basis.

Kirjanpidon luotettavuus

Tutkimuksen tavoitteena on selvittää millainen on luotettava kirjanpito, ja kuinka tilintarkastaja ja verotarkastaja varmistavat kirjanpidon luotettavuuden. Tutkimusmetodologiana käytetään käsiteanalyyttista tutkimusotetta. Tutkimuksessa tarkastellaan, kuinka kirjanpito ja tilinpaatos muodostuvat lakien ja hyvän kirjanpitotavan säätelemänä. Tilinpäätöksen tulee antaa oikeat ja riittävät tiedot yrityksen toiminnan tuloksesta ja taloudellisesta asemasta. Luotettava kirjanpito on ajanmukaista ja täydellistä. Se pitää yrityksen liiketapahtumat erillään yrityksen sidosryhmien liiketapahtumista ja omaisuudesta, täyttää todennettavuuden vaatimukset ja on laadittu sekä varovaisuuden periaatetta että kaikkia muita kirjanpidon yleisiä periaatteita noudattaen. Tilintarkastaja ja verotarkastaja tarkastavat kirjanpidon luotettavuutta. Jokaisella osakeyhtiöllä on velvollisuus toimittaa tilintarkastus. Verotarkastusta ei pystytä toimittamaan kaikissa yhtiöissä jälkiverotusaikana, vaan verotarkastuksella on voimakas virheitä ennaltaehkäisevä vaikutus. Tilintarkastuskertomus on julkinen asiakirja. Yrityksen kaikki sidosryhmät voivat hyödyntää tilintarkastajan lausuntoja. Verotarkastus palvelee lähinnä verotusta. Tilintarkastajan tulee noudattaa työssään hyvää tilintarkastustapaa, verotarkastajan hyvää verotarkastustapaa.

Non-Linear Journal Bearing Model for Analysis of Superharmonic Vibrations of Rotor Systems

A rotating machine usually consists of a rotor and bearings that supports it. The nonidealities in these components may excite vibration of the rotating system. The uncontrolled vibrations may lead to excessive wearing of the components of the rotating machine or reduce the process quality. Vibrations may be harmful even when amplitudes are seemingly low, as is usually the case in superharmonic vibration that takes place below the first critical speed of the rotating machine. Superharmonic vibration is excited when the rotational velocity of the machine is a fraction of the natural frequency of the system. In such a situation, a part of the machine’s rotational energy is transformed into vibration energy. The amount of vibration energy should be minimised in the design of rotating machines. The superharmonic vibration phenomena can be studied by analysing the coupled rotor-bearing system employing a multibody simulation approach. This research is focused on the modelling of hydrodynamic journal bearings and rotorbearing systems supported by journal bearings. In particular, the non-idealities affecting the rotor-bearing system and their effect on the superharmonic vibration of the rotating system are analysed. A comparison of computationally efficient journal bearing models is carried out in order to validate one model for further development. The selected bearing model is improved in order to take the waviness of the shaft journal into account. The improved model is implemented and analyzed in a multibody simulation code. A rotor-bearing system that consists of a flexible tube roll, two journal bearings and a supporting structure is analysed employing the multibody simulation technique. The modelled non-idealities are the shell thickness variation in the tube roll and the waviness of the shaft journal in the bearing assembly. Both modelled non-idealities may cause subharmonic resonance in the system. In multibody simulation, the coupled effect of the non-idealities can be captured in the analysis. Additionally one non-ideality is presented that does not excite the vibrations itself but affects the response of the rotorbearing system, namely the waviness of the bearing bushing which is the non-rotating part of the bearing system. The modelled system is verified with measurements performed on a test rig. In the measurements the waviness of bearing bushing was not measured and therefore it’s affect on the response was not verified. In conclusion, the selected modelling approach is an appropriate method when analysing the response of the rotor-bearing system. When comparing the simulated results to the measured ones, the overall agreement between the results is concluded to be good.

Vasicek interest rate model

Tässä tutkielmassa estimoidaan korkomallin parametrit Maximum likelihood metodilla sekä näytetään kuinka mallintaa lyhyen koron evoluutiota ja korkokäyrän rakennetta.

Radio Frequency Measurement Method for Detecting Bearing Currents in Induction Motors

Induction motors are widely used in industry, and they are generally considered very reliable. They often have a critical role in industrial processes, and their failure can lead to significant losses as a result of shutdown times. Typical failures of induction motors can be classified into stator, rotor, and bearing failures. One of the reasons for a bearing damage and eventually a bearing failure is bearing currents. Bearing currents in induction motors can be divided into two main categories; classical bearing currents and inverter-induced bearing currents. A bearing damage caused by bearing currents results, for instance, from electrical discharges that take place through the lubricant film between the raceways of the inner and the outer ring and the rolling elements of a bearing. This phenomenon can be considered similar to the one of electrical discharge machining, where material is removed by a series of rapidly recurring electrical arcing discharges between an electrode and a workpiece. This thesis concentrates on bearing currents with a special reference to bearing current detection in induction motors. A bearing current detection method based on radio frequency impulse reception and detection is studied. The thesis describes how a motor can work as a “spark gap” transmitter and discusses a discharge in a bearing as a source of radio frequency impulse. It is shown that a discharge, occurring due to bearing currents, can be detected at a distance of several meters from the motor. The issues of interference, detection, and location techniques are discussed. The applicability of the method is shown with a series of measurements with a specially constructed test motor and an unmodified frequency-converter-driven motor. The radio frequency method studied provides a nonintrusive method to detect harmful bearing currents in the drive system. If bearing current mitigation techniques are applied, their effectiveness can be immediately verified with the proposed method. The method also gives a tool to estimate the harmfulness of the bearing currents by making it possible to detect and locate individual discharges inside the bearings of electric motors.

Essays on pricing of risk and international linkage of Russian stock market

Last two decades have seen a rapid change in the global economic and financial situation; the economic conditions in many small and large underdeveloped countries started to improve and they became recognized as emerging markets. This led to growth in the amounts of global investments in these countries, partly spurred by expectations of higher returns, favorable risk-return opportunities, and better diversification alternatives to global investors. This process, however, has not been without problems and it has emphasized the need for more information on these markets. In particular, the liberalization of financial markets around the world, globalization of trade and companies, recent formation of economic and regional blocks, and the rapid development of underdeveloped countries during the last two decades have brought a major challenge to the financial world and researchers alike. This doctoral dissertation studies one of the largest emerging markets, namely Russia. The motivation why the Russian equity market is worth investigating includes, among other factors, its sheer size, rapid and robust economic growth since the turn of the millennium, future prospect for international investors, and a number of important major financial reforms implemented since the early 1990s. Another interesting feature of the Russian economy, which gives motivation to study Russian market, is Russia’s 1998 financial crisis, considered as one of the worst crisis in recent times, affecting both developed and developing economies. Therefore, special attention has been paid to Russia’s 1998 financial crisis throughout this dissertation. This thesis covers the period from the birth of the modern Russian financial markets to the present day, Special attention is given to the international linkage and the 1998 financial crisis. This study first identifies the risks associated with Russian market and then deals with their pricing issues. Finally some insights about portfolio construction within Russian market are presented. The first research paper of this dissertation considers the linkage of the Russian equity market to the world equity market by examining the international transmission of the Russia’s 1998 financial crisis utilizing the GARCH-BEKK model proposed by Engle and Kroner. Empirical results shows evidence of direct linkage between the Russian equity market and the world market both in regards of returns and volatility. However, the weakness of the linkage suggests that the Russian equity market was only partially integrated into the world market, even though the contagion can be clearly seen during the time of the crisis period. The second and the third paper, co-authored with Mika Vaihekoski, investigate whether global, local and currency risks are priced in the Russian stock market from a US investors’ point of view. Furthermore, the dynamics of these sources of risk are studied, i.e., whether the prices of the global and local risk factors are constant or time-varying over time. We utilize the multivariate GARCH-M framework of De Santis and Gérard (1998). Similar to them we find price of global market risk to be time-varying. Currency risk also found to be priced and highly time varying in the Russian market. Moreover, our results suggest that the Russian market is partially segmented and local risk is also priced in the market. The model also implies that the biggest impact on the US market risk premium is coming from the world risk component whereas the Russian risk premium is on average caused mostly by the local and currency components. The purpose of the fourth paper is to look at the relationship between the stock and the bond market of Russia. The objective is to examine whether the correlations between two classes of assets are time varying by using multivariate conditional volatility models. The Constant Conditional Correlation model by Bollerslev (1990), the Dynamic Conditional Correlation model by Engle (2002), and an asymmetric version of the Dynamic Conditional Correlation model by Cappiello et al. (2006) are used in the analysis. The empirical results do not support the assumption of constant conditional correlation and there was clear evidence of time varying correlations between the Russian stocks and bond market and both asset markets exhibit positive asymmetries. The implications of the results in this dissertation are useful for both companies and international investors who are interested in investing in Russia. Our results give useful insights to those involved in minimising or managing financial risk exposures, such as, portfolio managers, international investors, risk analysts and financial researchers. When portfolio managers aim to optimize the risk-return relationship, the results indicate that at least in the case of Russia, one should account for the local market as well as currency risk when calculating the key inputs for the optimization. In addition, the pricing of exchange rate risk implies that exchange rate exposure is partly non-diversifiable and investors are compensated for bearing the risk. Likewise, international transmission of stock market volatility can profoundly influence corporate capital budgeting decisions, investors’ investment decisions, and other business cycle variables. Finally, the weak integration of the Russian market and low correlations between Russian stock and bond market offers good opportunities to the international investors to diversify their portfolios.

Osakeindeksiobligaation fair value Case: SHB Paras Kolmesta 5010

Tutkielmassa selvitetään monimutkaisen indeksiobligaation arvon määritystä obligaation juoksuaikana. Tutkittava indeksiobligaatio sijoittaa osakkeisiin, korkoon ja raaka aineisiin. Kyseisessä indeksi-obligaatiossa sijoitetaan korioptioihin ja ne ovat lisäksi niiltä osin kvantto optioita, kun positio on ollut tarpeen suojata valuutta kurssimuutoksia vastaan. Tämän lisäksi indeksiobligaatio sijoittaa nolla kuponkilainaan. Sijoittajalle on haastavaa ymmärtää oikein ja läpinäkyvästi monimutkaisen osakeindeksiobligaation arvonmääritystä sen juoksuaikana. Tässä tutkielmassa avataan monimutkaisen osakeindeksiobligaation arvonmäärityksen perusteet. Tutkielmassa huomataan, että sijoittajalla voi helposti olla vaara mielikuva siitä, miten arvo määrittyy. Tämä johtuu siitä, että arvonmääritys eroaa huomattavasti siitä mikä käy ilmi velkakirjan ehdoissa. Tutkielman keskeisin anti on se, että kyseinen osakeindeksiobligaatio antaa heikkoa tuottoa kesken juoksuajan, mikäli joko osakkeet, raaka-aineet tai korot kehittyvät negatiivisesti. Lisaksi raaka aineoptioiden hinnan määritys eroaa siitä, mitä sijoittaja olettaa sen olevan velkakirjan ehtoja lukiessaan. Raaka-aineiden hinnat määritellään forward hinnoista

Kansainvälisten tilinpäätösstandardien ja vakavaraisuussäännöstön vaikutukset Suomessa toimivien vähittäispankkien vakavaraisuuteen laskusuhdanteessa

Globaalin rahoituskriisin myötä pankkien vakavaraisuus on noussut yleisen kiinnostuksen kohteeksi. Pankkien toimintaa säädellään tarkasti ja kriisin esille nostamien ongelmakohtien perusteella säännöksiin ollaan edelleen tekemässä muutoksia. Tämän tutkimuksen tavoitteena on selvittää minkälaiset vaikutukset kansainvälisillä tilinpäätösstandardeilla, IFRS, ja uudistetulle vakavaraisuussäännöstöllä, Basel 2, on pankkien vakavaraisuuteen laskusuhdanteessa. Tutkimus toteutettiin tutkimalla viiden Suomessa toimivan pankin raportointia. Tutkimuksen tuloksena nousi esille suurimpana vakavaraisuuteen vaikuttavana tekijänä Basel 2:n käyttöönotto. Tämän lisäksi pankkien kasvanut luottoriski, lisääntyneet arvonalentumiskirjaukset lainoista ja muista saamisista sekä käyvän arvon käsittelyn aiheuttamat alaskirjaukset vaikuttivat tutkimusproposition mukaisesti pankkien vakavaraisuuteen, mutta pankkien väliltä löytyi merkittäviä eroja.

Multilevel converter modulation: implementation and analysis

Multilevel converters provide an attractive solution to bring the benefits of speed-controlled rotational movement to high-power applications. Therefore, multilevel inverters have attracted wide interest in both the academic community and in the industry for the past two decades. In this doctoral thesis, modulation methods suitable especially for series connected H-bridge multilevel inverters are discussed. A concept of duty cycle modulation is presented and its modification is proposed. These methods are compared with other well-known modulation schemes, such as space-vector pulse width modulation and carrier-based modulation schemes. The advantage of the modified duty-cycle modulation is its algorithmic simplicity. A similar mathematical formulation for the original duty cycle modulation is proposed. The modified duty cycle modulation is shown to produce well-formed phase-to-neutral voltages that have lower total harmonic distortion than the space-vector pulse width modulation and the duty cycle modulation. The space-vector-based solution and the duty cycle modulation, on the other hand, result in a better-quality line-to-line voltage and current waveform. The voltage of the DC links in the modules of the series-connected H-bridge inverter are shown to fluctuate while they are under load. The fluctuation causes inaccuracies in the voltage production, which may result in a failure of the flux estimator in the controller. An extension for upper-level modulation schemes, which changes the switching instants of the inverter so that the output voltage meets the reference voltage accurately regardless of the DC link voltages, is proposed. The method is shown to reduce the error to a very low level when a sufficient switching frequency is used. An appropriate way to organize the switching instants of the multilevel inverter is to make only one-level steps at a time. This causes restrictions on the dynamical features of the modulation schemes. The produced voltage vector cannot be rotated several tens of degrees in a single switching period without violating the above-mentioned one-level-step rule. The dynamical capabilities of multilevel inverters are analyzed in this doctoral thesis, and it is shown that the multilevel inverters are capable of operating even in dynamically demanding metal industry applications. In addition to the discussion on modulation schemes, an overvoltage in multilevel converter drives caused by cable reflection is addressed. The voltage reflection phenomenon in drives with long feeder cables causes premature insulation deterioration and also affects the commonmode voltage, which is one of the main reasons for bearing currents. Bearing currents, on the other hand, cause fluting in the bearings, which results in premature bearing failure. The reflection phenomenon is traditionally prevented by filtering, but in this thesis, a modulationbased filterless method to mitigate the overvoltage in multilevel drives is proposed. Moreover, the mitigation method can be implemented as an extension for upper-level modulation schemes. The method exploits the oscillations caused by two consecutive voltage edges so that the sum of the oscillations results in a mitigated peak of the overvoltage. The applicability of the method is verified by simulations together with experiments with a full-scale prototype.

Structural studies on enzymes of biotechnological and biomedical interest

Structural studies of proteins aim at elucidating the atomic details of molecular interactions in biological processes of living organisms. These studies are particularly important in understanding structure, function and evolution of proteins and in defining their roles in complex biological settings. Furthermore, structural studies can be used for the development of novel properties in biomolecules of environmental, industrial and medical importance. X-ray crystallography is an invaluable tool to obtain accurate and precise information about the structure of proteins at the atomic level. Glutathione transferases (GSTs) are amongst the most versatile enzymes in nature. They are able to catalyze a wide variety of conjugation reactions between glutathione (GSH) and non-polar components containing an electrophilic carbon, nitrogen or sulphur atom. Plant GSTs from the Tau class (a poorly characterized class) play an important role in the detoxification of xenobiotics and stress tolerance. Structural studies were performed on a Tau class fluorodifen-inducible glutathione transferase from Glycine max (GmGSTU4-4) complexed with GSH (2.7 Å) and a product analogue Nb-GSH (1.7 Å). The three-dimensional structure of the GmGSTU4-4-GSH complex revealed that GSH binds in different conformations in the two subunits of the dimer: in an ionized form in one subunit and a non-ionized form in the second subunit. Only the ionized form of the substrate may lead to the formation of a catalytically competent complex. Structural comparison between the GSH and Nb-GSH bound complexes revealed significant differences with respect to the hydrogen-bonding, electrostatic interaction pattern, the upper part of -helix H4 and the C-terminus of the enzyme. These differences indicate an intrasubunit modulation between the G-and Hsites suggesting an induced-fit mechanism of xenobiotic substrate binding. A novel binding site on the surface of the enzyme was also revealed. Bacterial type-II L-asparaginases are used in the treatment of haematopoietic diseases such as acute lymphoblastic leukaemia (ALL) and lymphomas due to their ability to catalyze the conversion of L-asparagine to L-aspartate and ammonia. Escherichia coli and Erwinia chrysanthemi asparaginases are employed for the treatment of ALL for over 30 years. However, serious side-effects affecting the liver and pancreas have been observed due to the intrinsic glutaminase activity of the administered enzymes. Structural studies on Helicobacter pylori L-asparaginase (HpA) were carried out in an effort to discover novel L-asparaginases with potential chemotherapeutic utility in ALL treatment. Detailed analysis of the active site geometry revealed structurally significant differences between HpA and other Lasparaginases that may be important for the biological activities of the enzyme and could be further exploited in protein engineering efforts.

Broadband excitation in the system identification of active magnetic bearing rotor systems

One of the targets of the climate and energy package of the European Union is to increase the energy efficiency in order to achieve a 20 percent reduction in primary energy use compared with the projected level by 2020. The energy efficiency can be improved for example by increasing the rotational speed of large electrical drives, because this enables the elimination of gearboxes leading to a compact design with lower losses. The rotational speeds of traditional bearings, such as roller bearings, are limited by mechanical friction. Active magnetic bearings (AMBs), on the other hand, allow very high rotational speeds. Consequently, their use in large medium- and high-speed machines has rapidly increased. An active magnetic bearing rotor system is an inherently unstable, nonlinear multiple-input, multiple-output system. Model-based controller design of AMBs requires an accurate system model. Finite element modeling (FEM) together with the experimental modal analysis provides a very accurate model for the rotor, and a linearized model of the magneticactuators has proven to work well in normal conditions. However, the overall system may suffer from unmodeled dynamics, such as dynamics of foundation or shrink fits. This dynamics can be modeled by system identification. System identification can also be used for on-line diagnostics. In this study, broadband excitation signals are adopted to the identification of an active magnetic bearing rotor system. The broadband excitation enables faster frequency response function measurements when compared with the widely used stepped sine and swept sine excitations. Different broadband excitations are reviewed, and the random phase multisine excitation is chosen for further study. The measurement times using the multisine excitation and the stepped sine excitation are compared. An excitation signal design with an analysis of the harmonics produced by the nonlinear system is presented. The suitability of different frequency response function estimators for an AMB rotor system are also compared. Additionally, analytical modeling of an AMB rotor system, obtaining a parametric model from the nonparametric frequency response functions, and model updating are discussed in brief, as they are key elements in the modeling for a control design. Theoretical methods are tested with a laboratory test rig. The results conclude that an appropriately designed random phase multisine excitation is suitable for the identification of AMB rotor systems.