75 resultados para OPEN PROBLEMS IN TOPOLOGY


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Työn tavoitteena oli synkronoida yleinen materiaalivirta tuotannon kanssa. Pyrkimyksenä oli virtaviivaistaa materiaalivirta, jotta materiaalin määrä, sekä turhat työvaiheet tuotantoalueella vähenisivät. Päämääränä oli vähentää materiaalilavojen määrää lattialla, sekä parantaa materiaalitoimitusten OTD (On-Time-Delivery) prosenttia.Teoreettinen osa käsittelee nykypäivän toimitusketjun tärkeimpiä elementtejä. Keskeisenä asiana perehdytään materiaalivirtaan ja sen tehokkaaseen hallintaan. Työ esittelee myös synkronisen johtamismallin periaatteet, sekä materiaalivirran synkronoimisen tuotannon kanssa.Empiirinen osuus kuvaa yrityksen materiaalihallinnan nykypäivän tilanteen, sen keskeiset ongelmat, sekä uuden toimintamalliehdotuksen. Työ esittelee kaksi pilottia, joiden tulokset varmistivat uuden virtaviivaistetun materiaalivirran ja täydennysmallin toimivuuden.Työn tulokset osoittavat, miten uusi materiaalin täydennysmalli vähentää materiaalilavojen, sekä jalostamattoman työn määrää tuotantoalueella.

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This master’s thesis aims to study and represent from literature how evolutionary algorithms are used to solve different search and optimisation problems in the area of software engineering. Evolutionary algorithms are methods, which imitate the natural evolution process. An artificial evolution process evaluates fitness of each individual, which are solution candidates. The next population of candidate solutions is formed by using the good properties of the current population by applying different mutation and crossover operations. Different kinds of evolutionary algorithm applications related to software engineering were searched in the literature. Applications were classified and represented. Also the necessary basics about evolutionary algorithms were presented. It was concluded, that majority of evolutionary algorithm applications related to software engineering were about software design or testing. For example, there were applications about classifying software production data, project scheduling, static task scheduling related to parallel computing, allocating modules to subsystems, N-version programming, test data generation and generating an integration test order. Many applications were experimental testing rather than ready for real production use. There were also some Computer Aided Software Engineering tools based on evolutionary algorithms.

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The goal was to define how growth creates problems in small companies with a staff of uner 20, and how the problems are solved. It is not about fast growing companies, but about smoothly or even slowly growing companies. The growth is started through the turnover and the main motive is to have a economic stability. Almost all the companies felt that the main reason for this strate-gic growth was to increase the competitivety. Growth was mainly from the domestic market, and new products and new markets. The biggest problem with this growth was providing capital and also a lack of reas-surance. In additinon to this it was dificult to find suitable personnel and there was a lack of time needed to plan and develop the operation. The lack of product develop-ment, was found to be a problem to some extent, particulary in smaller companies. The follow-up of the finances take place mainly through the profit and loss account, income statement and balance sheets. Apart from that they find the follow up by pro-duct was important. Another important element was to have company tailor-made consulting/sparring in order to develop the operation.

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Tämä diplomityö käsittelee sääntöpohjaisen verkkoon pääsyn hallinnan (NAC) ratkaisuja arkkitehtonisesta näkökulmasta. Työssä käydään läpi Trusted Computing Groupin, Microsoft Corporationin, Juniper Networksin sekä Cisco Systemsin NAC-ratkaisuja. NAC koostuu joukosta uusia sekä jo olemassa olevia teknologioita, jotka auttavat ennalta määriteltyyn sääntökantaan perustuen hallitsemaan suojattuun verkkoon pyrkivien laitteiden tietoliikenneyhteyksiä. Käyttäjän tunnistamisen lisäksi NAC pystyy rajoittamaan verkkoon pääsyä laitekohtaisten ominaisuuksien perusteella, esimerkiksi virustunnisteisiin ja käyttöjärjestelmäpäivityksiin liittyen ja paikkaamaan tietyin rajoituksin näissä esiintyviä puutteita verkkoon pääsyn sallimiseksi. NAC on verraten uusi käsite, jolta puuttuu tarkka määritelmä. Tästä johtuen nykymarkkinoilla myydään ominaisuuksiltaan puutteellisia tuotteita NAC-nimikkeellä. Standardointi eri valmistajien NAC-komponenttien yhteentoimivuuden takaamiseksi on meneillään, minkä perusteella ratkaisut voidaan jakaa joko avoimia standardeja tai valmistajakohtaisia standardeja noudattaviksi. Esitellyt NAC-ratkaisut noudattavat standardeja joko rajoitetusti tai eivät lainkaan. Mikään läpikäydyistä ratkaisuista ei ole täydellinen NAC, mutta Juniper Networksin ratkaisu nousee niistä potentiaalisimmaksi jatkokehityksen ja -tutkimuksen kohteeksi TietoEnator Processing & Networks Oy:lle. Eräs keskeinen ongelma NAC-konseptissa on työaseman tietoverkolle toimittama mahdollisesti valheellinen tietoturvatarkistuksen tulos, minkä perusteella pääsyä osittain hallitaan. Muun muassa tähän ongelmaan ratkaisuna voisi olla jo nykytietokoneista löytyvä TPM-siru, mikä takaa tiedon oikeellisuuden ja koskemattomuuden.

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Työssä on tutkittu sähkösuunnittelun projektityön hallintaa ja kehittämistä. Tavoitteena oli löytää ongelmia ja pyrkiä korjaamaan niitä, jotta suunnittelu olisi mahdollisimman toimivaa. Tutkimus perustuu kirjallisuuteen ja haastatteluihin. Työssä perehdytään kirjallisuuden avulla projektin peruskäsitteisiin ja hallintaan sekä sähkösuunnittelun projektin yleiseen toteutukseen. Haastattelujen avulla on selvitetty tämän hetkistä tilannetta sähkösuunnitteluprojektin hallinnasta ja siihen liittyvistä ongelmista Pöyryn Kouvolan konttorissa. Työn tuloksena on selvitetty merkittävimpiä ongelmia, jotka esiintyvät sähkösuunnitteluprojektissa. Työ keskittyy pääosin sähkösuunnitteluprojektin hallinnallisiin ongelmiin ja niiden toteutukseen. Kirjallisuuden ja haastattelujen pohjalta on koottu ohjeita sähkösuunnittelun projektinhallintaan

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The objective of this research was to study the role of key individuals in facilitation of technology enabled bottom-up innovation in large organization context. The development of innovation was followed from the point of view of individual actor (key individual) in two cases, through three levels: individual, team and organization, by using knowledge creation and innovation models. This study provides theoretical synthesis and framework through which the study is driven. The results of the study indicate, that in bottom-up initiated innovations the role of key individuals is still crucial, but innovation today is collective effort and there acts several entrepreneurial key individuals: innovator, user champion and organizational sponsor, whose collaboration and developing interaction drives innovation further. The team work is functional and fluent, but it meets great problems in interaction with organization. The large organizations should develop its practices and ability to react on emerging bottom-up initiations, in order to embed innovation to organization and gain sustainable innovation. In addition, bottom-up initiated innovations are demonstrations of peoples knowing, tacit knowledge and therefore renewing of an organization.

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Performance standards for Positron emission tomography (PET) were developed to be able to compare systems from different generations and manufacturers. This resulted in the NEMA methodology in North America and the IEC in Europe. In practices, the NEMA NU 2- 2001 is the method of choice today. These standardized methods allow assessment of the physical performance of new commercial dedicated PET/CT tomographs. The point spread in image formation is one of the factors that blur the image. The phenomenon is often called the partial volume effect. Several methods for correcting for partial volume are under research but no real agreement exists on how to solve it. The influence of the effect varies in different clinical settings and it is likely that new methods are needed to solve this problem. Most of the clinical PET work is done in the field of oncology. The whole body PET combined with a CT is the standard investigation today in oncology. Despite the progress in PET imaging technique visualization, especially quantification of small lesions is a challenge. In addition to partial volume, the movement of the object is a significant source of error. The main causes of movement are respiratory and cardiac motions. Most of the new commercial scanners are in addition to cardiac gating, also capable of respiratory gating and this technique has been used in patients with cancer of the thoracic region and patients being studied for the planning of radiation therapy. For routine cardiac applications such as assessment of viability and perfusion only cardiac gating has been used. However, the new targets such as plaque or molecular imaging of new therapies require better control of the cardiac motion also caused by respiratory motion. To overcome these problems in cardiac work, a dual gating approach has been proposed. In this study we investigated the physical performance of a new whole body PET/CT scanner with NEMA standard, compared methods for partial volume correction in PET studies of the brain and developed and tested a new robust method for dual cardiac-respiratory gated PET with phantom, animal and human data. Results from performance measurements showed the feasibility of the new scanner design in 2D and 3D whole body studies. Partial volume was corrected, but there is no best method among those tested as the correction also depends on the radiotracer and its distribution. New methods need to be developed for proper correction. The dual gating algorithm generated is shown to handle dual-gated data, preserving quantification and clearly eliminating the majority of contraction and respiration movement

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Coastal birds are an integral part of coastal ecosystems, which nowadays are subject to severe environmental pressures. Effective measures for the management and conservation of seabirds and their habitats call for insight into their population processes and the factors affecting their distribution and abundance. Central to national and international management and conservation measures is the availability of accurate data and information on bird populations, as well as on environmental trends and on measures taken to solve environmental problems. In this thesis I address different aspects of the occurrence, abundance, population trends and breeding success of waterbirds breeding on the Finnish coast of the Baltic Sea, and discuss the implications of the results for seabird monitoring, management and conservation. In addition, I assess the position and prospects of coastal bird monitoring data, in the processing and dissemination of biodiversity data and information in accordance with the Convention on Biological Diversity (CBD) and other national and international commitments. I show that important factors for seabird habitat selection are island area and elevation, water depth, shore openness, and the composition of island cover habitats. Habitat preferences are species-specific, with certain similarities within species groups. The occurrence of the colonial Arctic Tern (Sterna paradisaea) is partly affected by different habitat characteristics than its abundance. Using long-term bird monitoring data, I show that eutrophication and winter severity have reduced the populations of several Finnish seabird species. A major demographic factor through which environmental changes influence bird populations is breeding success. Breeding success can function as a more rapid indicator of sublethal environmental impacts than population trends, particularly for long-lived and slowbreeding species, and should therefore be included in coastal bird monitoring schemes. Among my target species, local breeding success can be shown to affect the populations of the Mallard (Anas platyrhynchos), the Eider (Somateria mollissima) and the Goosander (Mergus merganser) after a time lag corresponding to their species-specific recruitment age. For some of the target species, the number of individuals in late summer can be used as an easier and more cost-effective indicator of breeding success than brood counts. My results highlight that the interpretation and application of habitat and population studies require solid background knowledge of the ecology of the target species. In addition, the special characteristics of coastal birds, their habitats, and coastal bird monitoring data have to be considered in the assessment of their distribution and population trends. According to the results, the relationships between the occurrence, abundance and population trends of coastal birds and environmental factors can be quantitatively assessed using multivariate modelling and model selection. Spatial data sets widely available in Finland can be utilised in the calculation of several variables that are relevant to the habitat selection of Finnish coastal species. Concerning some habitat characteristics field work is still required, due to a lack of remotely sensed data or the low resolution of readily available data in relation to the fine scale of the habitat patches in the archipelago. While long-term data sets exist for water quality and weather, the lack of data concerning for instance the food resources of birds hampers more detailed studies of environmental effects on bird populations. Intensive studies of coastal bird species in different archipelago areas should be encouraged. The provision and free delivery of high-quality coastal data concerning bird populations and their habitats would greatly increase the capability of ecological modelling, as well as the management and conservation of coastal environments and communities. International initiatives that promote open spatial data infrastructures and sharing are therefore highly regarded. To function effectively, international information networks, such as the biodiversity Clearing House Mechanism (CHM) under the CBD, need to be rooted at regional and local levels. Attention should also be paid to the processing of data for higher levels of the information hierarchy, so that data are synthesized and developed into high-quality knowledge applicable to management and conservation.

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There are several factors affecting network performance. Some of these can be controlled whereas the others are more fixed. These factors are studied in this thesis from the wide area network (WAN) perspective and the focus is on corporate networks. Another area of interest is the behavior of application protocols when used through WAN. The aim is to study the performance of commonly used application protocols in corporate networks. After identifying the performance problems in corporate WANs the thesis concentrates on methods for improving WAN performance. WAN acceleration is presented as a possible solution. The different acceleration methods are discussed in order to give the reader a theoretical view on how the accelerators can improve WAN performance. Guidelines on the installation of accelerators into a network are also discussed. After a general overview on accelerators is given, one accelerator vendor currently on market is selected for a further analysis. The work is also a case study where two accelerators are installed into a target company network for testing purposes. The tests are performed with three different application protocols that have been identified as critical applications for the target corporation. The aim of the tests is to serve as a proof of concept for WAN acceleration in the target network.

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Synchronous motors are used mainly in large drives, for example in ship propulsion systems and in steel factories' rolling mills because of their high efficiency, high overload capacity and good performance in the field weakening range. This, however, requires an extremely good torque control system. A fast torque response and a torque accuracy are basic requirements for such a drive. For large power, high dynamic performance drives the commonly known principle of field oriented vector control has been used solely hitherto, but nowadays it is not the only way to implement such a drive. A new control method Direct Torque Control (DTC) has also emerged. The performance of such a high quality torque control as DTC in dynamically demanding industrial applications is mainly based on the accurate estimate of the various flux linkages' space vectors. Nowadays industrial motor control systems are real time applications with restricted calculation capacity. At the same time the control system requires a simple, fast calculable and reasonably accurate motor model. In this work a method to handle these problems in a Direct Torque Controlled (DTC) salient pole synchronous motor drive is proposed. A motor model which combines the induction law based "voltage model" and motor inductance parameters based "current model" is presented. The voltage model operates as a main model and is calculated at a very fast sampling rate (for example 40 kHz). The stator flux linkage calculated via integration from the stator voltages is corrected using the stator flux linkage computed from the current model. The current model acts as a supervisor that prevents only the motor stator flux linkage from drifting erroneous during longer time intervals. At very low speeds the role of the current model is emphasised but, nevertheless, the voltage model always stays the main model. At higher speeds the function of the current model correction is to act as a stabiliser of the control system. The current model contains a set of inductance parameters which must be known. The validation of the current model in steady state is not self evident. It depends on the accuracy of the saturated value of the inductances. Parameter measurement of the motor model where the supply inverter is used as a measurement signal generator is presented. This so called identification run can be performed prior to delivery or during drive commissioning. A derivation method for the inductance models used for the representation of the saturation effects is proposed. The performance of the electrically excited synchronous motor supplied with the DTC inverter is proven with experimental results. It is shown that it is possible to obtain a good static accuracy of the DTC's torque controller for an electrically excited synchronous motor. The dynamic response is fast and a new operation point is achieved without oscillation. The operation is stable throughout the speed range. The modelling of the magnetising inductance saturation is essential and cross saturation has to be considered as well. The effect of cross saturation is very significant. A DTC inverter can be used as a measuring equipment and the parameters needed for the motor model can be defined by the inverter itself. The main advantage is that the parameters defined are measured in similar magnetic operation conditions and no disagreement between the parameters will exist. The inductance models generated are adequate to meet the requirements of dynamically demanding drives.

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Problems in the mobile services are complex where the lack of the user analysis is not the modest issue. User centered design has increasingly become as a basis for the design of mobile services. The concept of user centered design gives end-user extensive attention at each stage of the design process. Mobile service providers want to offer experiences for users and clearly the users look for services that can provide pleasant experiences. In this thesis, the elements of user experience in mobile internet were studied as well as user experience measuring methods were researched. This study was looking for user experience measuring metrics and methods to specify new factors to measure user experience. During this thesis research project an application called CEM4Mobile was designed and implemented. CEM4Mobile is an application for observing and analysing user experience based on the user activity and behaviour. As a result of this thesis, a collection of user experience elements and measuring metrics were found. The elements and metrics were designed and implemented to CEM4Mobile product, which measures user experience. It was found out that the user experience measuring methods were based on interaction between two people but CEM4Mobile makes user observation programmatic.

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The primary objective of this thesis was to research delivery reliability of mill business unit of a forest industry company, especially timely and quantitative accuracy of sales orders. Delivery reliability is an important factor of customer satisfaction, which has a great influence for success of a company. The secondary objective was to find out reasons for possible problems of delivery reliability and give propositions for improvable performances. The empirical part of the thesis based on reporting database of the forest industry company’s ERP-software and detailed information of the mill system. The delivery reliability results of the mill business unit were compared to delivery reliability of similar mill business unit inside the forest industry company. The research results expressed problems in the supply chain. The delivery reliability reporting should be also developed further. This would advance delivery reliability monitoring. The improvement propositions of the thesis were logistic operation mode estimation, particular benchmarking of the compared mill business unit and more detailed survey on production delivery reliability.

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Demand forecasting is one of the fundamental managerial tasks. Most companies do not know their future demands, so they have to make plans based on demand forecasts. The literature offers many methods and approaches for producing forecasts. When selecting the forecasting approach, companies need to estimate the benefits provided by particular methods, as well as the resources that applying the methods call for. Former literature points out that even though many forecasting methods are available, selecting a suitable approach and implementing and managing it is a complex cross-functional matter. However, research that focuses on the managerial side of forecasting is relatively rare. This thesis explores the managerial problems that are involved when demand forecasting methods are applied in a context where a company produces products for other manufacturing companies. Industrial companies have some characteristics that differ from consumer companies, e.g. typically a lower number of customers and closer relationships with customers than in consumer companies. The research questions of this thesis are: 1. What kind of challenges are there in organizing an adequate forecasting process in the industrial context? 2. What kind of tools of analysis can be utilized to support the improvement of the forecasting process? The main methodological approach in this study is design science, where the main objective is to develop tentative solutions to real-life problems. The research data has been collected from two organizations. Managerial problems in organizing demand forecasting can be found in four interlinked areas: 1. defining the operational environment for forecasting, 2. defining the forecasting methods, 3. defining the organizational responsibilities, and 4. defining the forecasting performance measurement process. In all these areas, examples of managerial problems are described, and approaches for mitigating these problems are outlined.

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The size and complexity of projects in the software development are growing very fast. At the same time, the proportion of successful projects is still quite low according to the previous research. Although almost every project's team knows main areas of responsibility which would help to finish project on time and on budget, this knowledge is rarely used in practice. So it is important to evaluate the success of existing software development projects and to suggest a method for evaluating success chances which can be used in the software development projects. The main aim of this study is to evaluate the success of projects in the selected geographical region (Russia-Ukraine-Belarus). The second aim is to compare existing models of success prediction and to determine their strengths and weaknesses. Research was done as an empirical study. A survey with structured forms and theme-based interviews were used as the data collection methods. The information gathering was done in two stages. At the first stage, project manager or someone with similar responsibilities answered the questions over Internet. At the second stage, the participant was interviewed; his or her answers were discussed and refined. It made possible to get accurate information about each project and to avoid errors. It was found out that there are many problems in the software development projects. These problems are widely known and were discussed in literature many times. The research showed that most of the projects have problems with schedule, requirements, architecture, quality, and budget. Comparison of two models of success prediction presented that The Standish Group overestimates problems in project. At the same time, McConnell's model can help to identify problems in time and avoid troubles in future. A framework for evaluating success chances in distributed projects was suggested. The framework is similar to The Standish Group model but it was customized for distributed projects.

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The purpose of this study was to define the key challenges for Finnish companies in doing business in Russia. The study consists of a theoretical and an empirical part and is conducted as a quantitative study. The theoretical framework was build around capital structure, cost of capital and emerging market theories. The findings suggest that the firms in the sample seek growth mainly from emerging markets. These research results also indicate that challenges are visible in emerging market environment. Challenges that companies are facing in Russian market are mainly connected with legislation, communication and language problems. In addition, companies’ profitability has changed during the financial crisis, which has been the main reason for the negative changes in companies’ profitability. Even though the financial crisis has had a strong effect on the worldwide economy, the firms in the sample are not postponing their investments to Russia, because of lack of new financing or unfavorable credit terms.