Neural network enhanced self tuning adaptive control application for non-linear control of dynamic systems

The main theme of research of this project concerns the study of neutral networks to control uncertain and non-linear control systems. This involves the control of continuous time, discrete time, hybrid and stochastic systems with input, state or output constraints by ensuring good performances. A great part of this project is devoted to the opening of frontiers between several mathematical and engineering approaches in order to tackle complex but very common non-linear control problems. The objectives are: 1. Design and develop procedures for neutral network enhanced self-tuning adaptive non-linear control systems; 2. To design, as a general procedure, neural network generalised minimum variance self-tuning controller for non-linear dynamic plants (Integration of neural network mapping with generalised minimum variance self-tuning controller strategies); 3. To develop a software package to evaluate control system performances using Matlab, Simulink and Neural Network toolbox. An adaptive control algorithm utilising a recurrent network as a model of a partial unknown non-linear plant with unmeasurable state is proposed. Appropriately, it appears that structured recurrent neural networks can provide conveniently parameterised dynamic models for many non-linear systems for use in adaptive control. Properties of static neural networks, which enabled successful design of stable adaptive control in the state feedback case, are also identified. A survey of the existing results is presented which puts them in a systematic framework showing their relation to classical self-tuning adaptive control application of neural control to a SISO/MIMO control. Simulation results demonstrate that the self-tuning design methods may be practically applicable to a reasonably large class of unknown linear and non-linear dynamic control systems.

e-Business in supply chain management

E-business is concerned with the use of the Internet to link companies with their suppliers, customers and other trading partners. As a business concept, it has evolved significantly since its introduction in the 1990’s in parallel with the rapid rate of development of information technology (IT) during this period. Supply chain management (SCM) is fundamentally concerned with integration of activities both with and between organisations. IT plays a crucial role in SCM as a key enabler of supply chain integration (SCI). This chapter sets out the role of e-business concepts in the context of the supply chain challenges faced by firms. It specifically explores the role of e-procurement as an example of how e-business concepts have been applied to one key SCM activity, namely purchasing and procurement. In this context, the chapter examines the nature and evolution of e-marketplaces and goes on to identify key adoption drivers and benefits based on recent research. This research identifies key adoption drivers and benefits but also recognises that there are many barriers that ongoing research needs to address if the potential of e-business is to be fulfilled.

Hálózat – A globális gazdaság kvázi szervezete (The business network – the quasi organization of the global economy)

A tanulmány célja, hogy értelmezze a globális gazdaság alapvető fontosságú építőelemét, az üzleti hálózatot, majd megvizsgálja annak felépítését és működésének főbb vezérlőelveit. Először az alapfogalmak – üzleti hálózat, ellátási lánc és ellátási háló – meghatározására és azok felépítésének bemutatására kerül sor. Ezt követően a cikk röviden ismerteti, hogy melyek voltak azok a vállalati gazdálkodás környezetében végbement változások, melyek a gazdaság hálózatosodását elősegítették és ennek kapcsán elvezettek az üzleti hálózatok versenyképességben játszott szerepének erősödéséhez. A szerző ugyanakkor bemutatja a kialakuló új gazdasági modell, az ún. hálózati gazdaság működési modelljének lényeges új tulajdonságait. A tanulmány ezután ismerteti az üzleti hálózat – s ezen belül az ellátási lánc – működtetésében meghatározó koordinációs mechanizmusokban megfigyelhető markáns változásokat. Végül részletesen ismerteti az üzleti hálózat két fő építőelemét: a hálózatot alkotó üzleti egységeknek, illetve a közöttük kialakuló kapcsolatoknak az alapvető típusait. ________ The aim of the paper is to present and interpret the basic building element of global business: the business network, its structure and operation. First basic terms – network, supply chain, supply network – are defined and described, than those changes are introduced that played significant role in increasing their importance. Characteristics of the new network economy are presented; especially changes in the coordination mechanism between cooperating parties in the network are demonstrated. Finally the two building blocks of global business networks: (i) nodes (business units) and (ii) threads (partnerships) are described in details.

Optimizing Supply Chain Performance in China with Country-Specific Supply Chain Coordination

The implementation of country-specific supply chain coordination techniques ensures an optimal global supply chain performance. This paper looks at success factors going with a supply chain coordination strategy within the global supply chain of a successful, medium-sized, privately-owned company, one having locations in North America (USA), Europe (Hungary) and Asia (China). Through the shown GSL’s Chinese plant, we will endeavor to argue that increased collaboration in the supply network with appropriate supply chain coordination brings down not only the inventory level but can also improve conformance quality and reduce quoted lead times.

Comportamento dinâmico da rede eléctrica da ilha de São Vicente em Cabo Verde: estabilidade de tensão

Neste trabalho é efectuado, não só o diagnóstico em regime permanente, mas também o estudo, simulação e análise do comportamento dinâmico da rede eléctrica da ilha de São Vicente em Cabo Verde. Os estudos de estabilidade transitória desempenham um importante papel, tanto no planeamento como na operação dos sistemas de potência. Tais estudos são realizados, em grande parte, através de simulação digital no domínio do tempo, utilizando integração numérica para resolver as equações não-lineares que modelam a dinâmica do sistema e dependem da existência de registos reais de perturbação (ex: osciloperturbografia). O objectivo do trabalho será também verificar a aplicabilidade dos requisitos técnicos que as unidades geradoras devem ter, no que concerne ao controlo de tensão, estabelecidos na futura regulamentação europeia desenvolvida pela ENTSO-E (European Network Transmission System Operator for Electricity). De entre os requisitos analisou-se a capacidade das máquinas existentes suportarem cavas de tensão decorrentes de curto-circuitos trifásicos simétricos, Fault Ride Through, no ponto de ligação à rede. Identificaram-se para o efeito os factores que influenciam a estabilidade desta rede, em regime perturbado nomeadamente: (i) duração do defeito, (ii) caracterização da carga, com e sem a presença do sistema de controlo de tensão (AVR) em unidades de geração síncronas. Na ausência de registos reais sobre o comportamento do sistema, conclui-se que este é sensível à elasticidade das cargas em particular do tipo potência constante, existindo risco de perda de estabilidade, neste caso, para defeitos superiores a 5ms sem AVR. A existência de AVR nesta rede afigura-se como indispensável para garantir estabilidade de tensão sendo contudo necessário proceder a uma correcta parametrização.

Desenvolvimento de um plano de manutenção preventiva na rede de distribuição de água de Lisboa

O presente relatório de estágio enquadra-se no âmbito do trabalho final de Mestrado do curso de Engenharia Civil, área de especialização em Hidráulica, do Instituto Superior de Engenharia de Lisboa, e incide na temática dos sistemas de distribuição de água. O estágio decorreu na empresa EPAL – Empresa Portuguesa das Águas Livres, S.A., e teve como objecto o desenvolvimento de um plano de manutenção preventiva para a rede de distribuição de água de Lisboa. Devido à crescente complexidade dos sistemas de abastecimento de água e à grande dispersão territorial dos diversos órgãos integrados na rede, surge a necessidade de desenvolver um sistema que permita simplificar o planeamento e a gestão das intervenções de inspecção e manutenção preventiva dos órgãos. Para esse efeito, recorreu-se a um software SIG (Sistema de Informação Geográfica) para proceder à sectorização da rede de distribuição de água em pequenos grupos (Polígonos), constituídos por um número determinado de órgãos de manobra e segurança. Esta metodologia permite organizar as intervenções em pequenos grupos e optimizar as rotinas de Inspecção diárias. No decorrer do estágio efectuou-se ainda um levantamento dos procedimentos de inspecção e manutenção dos diversos órgãos integrados na rede de distribuição de água de Lisboa, quer por acompanhamento de actividades com as equipas de inspecção, quer por recolha de recomendações junto dos fabricantes dos órgãos. Este levantamento permitiu elaborar fichas de procedimento para as actividades de inspecção e manutenção preventiva dos diversos órgãos, afim de serem usadas como referência pelos trabalhadores.

Modelização de equivalente eléctrico para rede de nervuras de folhas vegetais

A tese tem como objectivo principal a criação de um modelo equivalente eléctrico da rede de nervuras de algumas folhas vegetais e analisar o seu comportamento a estímulos eléctricos, analisando-se também a respectiva resposta em frequência. A motivação desta tese passa pela observação dos sistemas existentes na natureza. Neste caso, as folhas vegetais e analisar se são sistemas de ordem fraccionária ou não. Para a sua elaboração, fez-se uma breve abordagem à estrutura das plantas, sob o ponto de vista da botânica e elaborou-se um método de fotografia das amostras, mapeamento da rede de nervuras e medição dos segmentos que compõem essa mesma rede. A tese termina com um capítulo de resultados experimentais.

Modelação hidráulica de um sistema adutor em alta

Este relatório é fruto de um trabalho desenvolvido por um período de seis meses onde é apresentada uma breve introdução da empresa, bem como as políticas pelas quais ela funciona. São também descritas as formações obtidas e o plano de trabalhos seguido. Relativamente ao trabalho em si, o tema principal do trabalho desenvolvido, e tal como é apresentado no título deste relatório, é a modelação hidráulica de um sistema adutor em alta, isto é, onde foi elaborado um modelo para uma rede de abastecimento de água recorrendo aos registos de consumos fornecidos pela empresa Águas do Douro e Paiva, S.A.. É realizada uma descrição dos vários passos que levaram à sua elaboração e são apresentadas as conclusões relativas aos resultados obtidos. Uma vez que o trabalho incidiu sobre o funcionamento e aprendizagem de software apropriado, foram também retiradas conclusões/sugestões que poderão ser tomadas de forma a melhorar a experiência entre programas e utilizadores. Apesar do tempo disponível para a realização do plano de trabalhos ter demonstrado ser o suficiente para o cumprimento dos vários requisitos, foi também suficiente para permitir a realização de outros trabalhos que proporcionaram a aquisição de mais experiência no desenvolvimento de modelos em EPANET.

Transfer insensitive labeling technique (TILT): application to multislice functional perfusion imaging.

Cerebral blood flow can be studied in a multislice mode with a recently proposed perfusion sequence using inversion of water spins as an endogenous tracer without magnetization transfer artifacts. The magnetization transfer insensitive labeling technique (TILT) has been used for mapping blood flow changes at a microvascular level under motor activation in a multislice mode. In TILT, perfusion mapping is achieved by subtraction of a perfusion-sensitized image from a control image. Perfusion weighting is accomplished by proximal blood labeling using two 90 degrees radiofrequency excitation pulses. For control preparation the labeling pulses are modified such that they have no net effect on blood water magnetization. The percentage of blood flow change, as well as its spatial extent, has been studied in single and multislice modes with varying delays between labeling and imaging. The average perfusion signal change due to activation was 36.9 +/- 9.1% in the single-slice experiments and 38.1 +/- 7.9% in the multislice experiments. The volume of activated brain areas amounted to 1.51 +/- 0.95 cm3 in the contralateral primary motor (M1) area, 0.90 +/- 0.72 cc in the ipsilateral M1 area, 1.27 +/- 0.39 cm3 in the contralateral and 1.42 +/- 0.75 cm3 in the ipsilateral premotor areas, and 0.71 +/- 0.19 cm3 in the supplementary motor area.

Vendor Managed Inventory: the Critical Success Factors from the Manufacturer Point of View

Yritykset ovat pakotettuja erilaisiin yhteistyömuotoihin pärjätäkseen kiristyvässä kilpailussa. Yhteistyösuhteet kulkevat eri nimillä riippuen teollisuuden alasta ja siitä, missä kohtaa toimitusketjua ne toteutuvat, mutta periaatteessa kaikki pohjautuvat samaan ideaan kuin Vendor Managed Inventory (VMI); varastoon jakysyntään liittyvä tieto jaetaan toimitusketjun eri osapuolien kesken, jotta tuotanto, jakelu ja varastonhallinta olisi mahdollista optimoida. Vendor Managed Inventory on ideana yksinkertainen, mutta vaatii onnistuakseen paljon. Perusolettamus on, että toimittajan on kyettävä hallinnoimaan asiakkaan varastoa paremmin kuin asiakas itse. Tämä ei kuitenkaan ole mahdollista ilman riittävää yhteistyötä, oikeanlaista informaatiota tai sopivia tuoteominaisuuksia. Tämän työn tarkoitus on esitellä kriittiset menestystekijät valmistajan kannalta, kun näkyvyys todelliseen kysyntään on heikko ja kyseessäolevat tuotteet ovat ominaisuuksiltaan toimintamalliin huonosti soveltuvia. VMItoimintamallin soveltuvuus matkapuhelimia valmistavan yrityksen liiketoimintaan, sekä sen vaikutus asiakasyhteistyöhön, kannattavuuteen ja toiminnan tehostamiseen on myös tutkittu.

Riskienhallinta verkostotaloudessa. Case Varenso Oy

Tutkielman avulla pyrittiin edesauttamaan kohdeyrityksen riskienhallintaa verkostotaloudessa turvallisuusnäkökulmasta. Tutkielmassa tarkasteltiin neljän alihankkijayrityksen asennetta ja menettelytapoja turvallisuusjohtamisen, organisaation, toiminnan suunnittelun, toiminnan varmistamisen, sidosryhmien, riskien hallinnan, hätä- ja poikkeustilanteiden, turvallisuuskoulutuksen, tiedonkulun ja dokumentoinnin sekä mittaamisen osa-alueilta Turvallisuus kymppi menetelmää käyttäen. Tutkielma suoritettiin syksyn 2002 ja kevään 2003 aikana. Aiheen monitahoisuuden vuoksi asiaa tarkasteltiin hankintatoimen muuttuneen roolin, verkostotalouden, riskien ja riskienhallinnan kautta. Tutkielman lopputuloksena havaittiin, että verkostossa toimittaessa keskusyrityksen ja aliurakoitsijoiden riskeistä tulee yhteisiä, eikä niitä ei voida enää kokonaan erotella. Koulutuksen, tiedonkulun, mittaamisen, riskienhallinnan ja sidosryhmien välisen toiminnan luonne korostuu entisestään.

Outsourcing Challenges in Russia

The study focuses on the key factors in outsourcing from the viewpoint of manufacturing companies operating in Russia. The goal has been to give an overview of the different kinds of challenges companies might face in the case of outsourcing. Of particular interest are the possible risks which might originate from the subcontract relationship, as well as managing these risks. The empirical material for this qualitative interview study was collected from three large-scale manufacturing companies operating in food industry in Russia. Two of the interviewed companies were local Russian actors, and one was an international firm. According to the respondents, a big challenge is to find a suitable supplier in the Russian markets. If there are suppliers available, they may often not be capable of operating as outsourcing partners. The most common problems faced with suppliers are unstable quality and arbitrary pricing. Whether the suppliers are capable to offer activities which satisfy the company’s own and the end customers’ requirements, seems to be the biggest concern in the interviewed companies. This quality risk is managed by the strategy of multiple sourcing. Single sourcing is seen as an impossible option. The interviewed companies have no organised risk management with their external suppliers.

Insulation System in an Integrated Motor Compressor

A high-speed and high-voltage solid-rotor induction machine provides beneficial features for natural gas compressor technology. The mechanical robustness of the machine enables its use in an integrated motor-compressor. The technology uses a centrifugal compressor, which is mounted on the same shaft with the high-speed electrical machine driving it. No gearbox is needed as the speed is determined by the frequency converter. The cooling is provided by the process gas, which flows through the motor and is capable of transferring the heat away from the motor. The technology has been used in the compressors in the natural gas supply chain in the central Europe. New areas of application include natural gas compressors working at the wellheads of the subsea gas reservoir. A key challenge for the design of such a motor is the resistance of the stator insulation to the raw natural gas from the well. The gas contains water and heavy hydrocarbon compounds and it is far harsher than the sales gas in the natural gas supply network. The objective of this doctoral thesis is to discuss the resistance of the insulation to the raw natural gas and the phenomena degrading the insulation. The presence of partial discharges is analyzed in this doctoral dissertation. The breakdown voltage of the gas is measured as a function of pressure and gap distance. The partial discharge activity is measured on small samples representing the windings of the machine. The electrical field behavior is also modeled by finite element methods. Based on the measurements it has been concluded that the discharges are expected to disappear at gas pressures above 4 – 5 bar. The disappearance of discharges is caused by the breakdown strength of the gas, which increases as the pressure increases. Based on the finite element analysis, the physical length of a discharge seen in the PD measurements at atmospheric pressure was approximated to be 40 – 120 m. The chemical aging of the insulation when exposed to raw natural gas is discussed based on a vast set of experimental tests with the gas mixture representing the real gas mixture at the wellhead. The mixture was created by mixing dry hydrocarbon gas, heavy hydrocarbon compounds, monoethylene glycol, and water. The mixture was chosen to be more aggressive by increasing the amount of liquid substances. Furthermore, the temperature and pressure were increased, which resulted in accelerated test conditions. The time required to detect severe degradation was thus decreased. The test program included a comparison of materials, an analysis of the e ects of di erent compounds in the gas mixture, namely water and heavy hydrocarbons, on the aging, an analysis of the e ects of temperature and exposure duration, and also an analysis on the e ect of sudden pressure changes on the degradation of the insulating materials. It was found in the tests that an insulation consisting of mica, glass, and epoxy resin can tolerate the raw natural gas, but it experiences some degradation. The key material in the composite insulation is the resin, which largely defines the performance of the insulation system. The degradation of the insulation is mostly determined by the amount of gas mixture di used into it. The di usion was seen to follow Fick’s second law, but the coe cients were not accurately defined. The di usion was not sensitive to temperature, but it was dependent upon the thermodynamic state of the gas mixture, in other words, the amounts of liquid components in the gas. The weight increase observed was mostly related to heavy hydrocarbon compounds, which act as plasticizers in the epoxy resin. The di usion of these compounds is determined by the crosslink density of the resin. Water causes slight changes in the chemical structure, but these changes do not significantly contribute to the aging phenomena. Sudden changes in pressure can lead to severe damages in the insulation, because the motion of the di used gas is able to create internal cracks in the insulation. Therefore, the di usion only reduces the mechanical strength of the insulation, but the ultimate breakdown can potentially be caused by a sudden drop in the pressure of the process gas.

Spare part business analysis and development

The purpose of this Thesis was to comprehensively analyze and develop the spare part business in Company Oy’s five biggest product groups by searching development issues related to single spare parts’ supply chains as well as the spare part business process, make implementation plans for them and implement the plans when possible. The items were classified based on special characteristics of spare parts and on their actual sales volumes. The created item classes were examined for finding improvement possibilities. Management strategies for classified items were suggested. Vendors and customers were analyzed for supporting the comprehensive supply network development work. The effectiveness of the current spare part business process was analyzed in co-operation with the spare part teams in three business unit locations. Several items were taken away from inventories as uselessly stocked items. Price list related to core items with one of the main product group’s core item manufacturer was suggested to be expanded in Town A. Refinement equipment seal item supply chain management was seen important to develop in Town B. A new internal business process model was created for minimizing and enhancing the internal business between Company’s business units. SAP inventory reports and several other features were suggested to be changed or developed. Also the SAP data material management was seen very important to be developed continuously. Many other development issues related to spare parts’ supply chains and the work done in the business process were found. The need for investigating the development possibilities deeper became very clear during the project.

Strategic management of value networks: how to create value in cross-sector collaboration and partnerships

Cross-sector collaboration and partnerships have become an emerging and desired strategy in addressing huge social and environmental challenges. Despite its popularity, cross-sector collaboration management has proven to be very challenging. Even though cross-sector collaboration and partnership management have been widely studied and discussed in recent years, their effectiveness as well as their ability to create value with respect to the problems they address has remained very challenging. There is little or no evidence of their ability to create value. Regarding all these challenges, this study aims to explore how to manage cross-sector collaborations and partnerships to be able to improve their effectiveness and to create more value for all partners involved in collaboration as well as for customers. The thesis is divided into two parts. The first part comprises an overview of relevant literature (including strategic management, value networks and value creation theories), followed by presenting the results of the whole thesis and the contribution made by the study. The second part consists of six research publications, including both quantitative and qualitative studies. The chosen research strategy is triangulation, as the study includes four types of triangulation: (1) theoretical triangulation, (2) methodological triangulation, (3) data triangulation and (4) researcher triangulation. Two publications represent conceptual development, which are based on secondary data research. One publication is a quantitative study, carried out through a survey. The other three publications represent qualitative studies, based on case studies, where data was collected through interviews and workshops, with participation of managers from all three sectors: public, private and the third (nonprofit). The study consolidates the field of “strategic management of value networks,” which is proposed to be applied in the context of cross-sector collaboration and partnerships, with the aim of increasing their effectiveness and the process of value creation. Furthermore, the study proposes a first definition for the strategic management of value networks. The study also proposes and develops two strategy tools that are recommended to be used for the strategic management of value networks in cross-sector collaboration and partnerships. Taking a step forward, the study implements the strategy tools in practice, aiming to show and to demonstrate how new value can be created by using the developed strategy tools for the strategic management of value networks. This study makes four main contributions. (1) First, it brings a theoretical contribution by providing new insights and consolidating the field of strategic management of value networks, also proposing a first definition for the strategic management of value networks. (2) Second, the study makes a methodical contribution by proposing and developing two strategy tools for value networks of cross-sector collaboration: (a) value network mapping, a method that allows us to assess the current and the potential value network and (b) the Value Network Scorecard, a method of performance measurement and performance prediction in cross-sector collaboration. (3) Third, the study has managerial implications, offering new solutions and empirical evidence on how to increase the effectiveness of cross-sector collaboration and also allow managers to understand how new value can be created in cross-sector partnerships and how to get the full potential of collaboration. (4) And fourth, the study also has practical implications, allowing managers to understand how to use in practice the strategy tools developed in this study, providing discussions on the limitations regarding the proposed tools as well as general limitations involved in the study.