[lic] Perustieteiden korkeakoulu / SCI

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    Optimal reservoir computers for nonlinear systems of varying complexity
    (Aalto-yliopisto, 2023) Kärkkäinen, Pauliina; Linna, Riku; Tietotekniikan laitos; Department of Computer Science; Perustieteiden korkeakoulu; School of Science; Lampinen, Jouko
    Prediction and analysis of nonlinear systems is highly important in natural sciences, medicine, and engineering. In real-world complex systems of nonlinear dynamics the analysis relies largely on surrogate models. Reservoir computers (RC) have proven useful in replicating the climate of chaotic dynamics. The quality of surrogate models based on RCs is crucially dependent on judiciously determined optimal implementation that involves optimising both the reservoir network topology and the used hyperparameters. In this work, we explore how the topology of reservoir computers reflects in their performance in replicating and predicting systems of chaotic or merely nonlinear dynamics. We show that connectedness of the topology is significant to performance only when reproducing and predicting chaotic systems of sufficient complexity. This is done by systematically applying Bayesian optimisation to produce optimal reservoirs for each topology and using large ensembles of reservoirs. The dynamical systems used are Lorenz 63, coupled Wilson-Cowan oscillators and Kuramoto-Sivashinsky system. By applying RCs of different topologies to these systems, we show that reservoirs of unconnected nodes (RUN) outperform reservoirs of connected nodes for target systems whose estimated fractal dimension is d_f < 5.5 and that linked reservoirs are better for systems with d_f > 5.5. Inspection of Kuramoto-Sivashinsky systems up to dimension d_f = 13.5 did not show any difference between the performance of recursively and simply connected reservoir topologies. However, we anticipate that there may be another transition at a higher value of d_f, beyond which recursive neural networks (RNN) outperform non-recurrent connected reservoirs. Lastly, we show that judicious hyperparameter optimisation is crucial for obtaining reliable results.
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    Softala - a framework for coaching the students of software development to acquire sales and service skills required in small software companies
    (2014) Kivihalme, Minna; Kinnunen, Päivi; Perustieteiden korkeakoulu; Perustieteiden korkeakoulu; School of Science; Malmi, Lauri
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    Benefits and costs of radical open innovations
    (Aalto-yliopisto, 2018) Koivisto, Nina; Tuotantotalouden laitos; Department of Industrial Engineering and Management; Perustieteiden korkeakoulu; School of Science; Vartiainen, Matti
    This research consists of four independent articles in addition this synthesis. The research question is: What are the benefits and costs associated with the infusion of customer participation in radical innovations on the firm-level? According to the results, users do and co-create successful radical innovations - even if literature claims otherwise. The results support the crucial role of customers in companies’ innovation process. The radical innovations were most commonly claimed to come from outsiders. Frequently a radical innovation comes through people trying to solve a problem that’s relevant to them. Two benefits associated with the infusion of customer participation in the B2B radical innovation process are: using crowd for microtasking, and using a community for co-creation, the so-called white labelling. Co-creation with customers in open innovation can lead to a great success when creating a ‘trust network, but the biggest challenge is the resistance to change involving big and radical systems. The best methods for innovation research are diaries and workshops, but surveys are not good since the survey seemed to work in the past tense (‘Did you enjoy the graphics of the game?’), but in the innovation process future tense answers are wanted (‘What kind of game would you like to play?’). In this research it was found that lead users are a willing, untapped, and limitless resource of innovation for the development process in industries where users feel passionately about the service, and they are needed in fields lacking employees.
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    Applications of deep neural networks of assisting human learning
    (2017) Keurulainen, Antti; Perustieteiden korkeakoulu; Perustieteiden korkeakoulu; School of Science; Karhunen, Juha
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    Older employees' adjustment to a merger and their retirement intentions - The role of organizational identification, perceived procedural justice and work engagement
    (2016) Kupiainen, Olli-Jaakko; Lipponen, Jukka; Perustieteiden korkeakoulu; Perustieteiden korkeakoulu; School of Science; Järvenpää, Eila
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    Työyhteisön kehittämisen yhteys työhyvinvointiin ja työkykyyn teknologia-teollisuudessa
    (2016) Muinonen, Raija; Vartiainen, Matti; Tuotantotalouden laitos; Perustieteiden korkeakoulu; School of Science; Smeds, Riitta
    Työssäkäyvän väestön terveysongelmat, pienenevät ikäluokat ja varhaiset eläköitymiset aiheuttavat yrityksissä suuren tarpeen työkyvyn ylläpitämiselle ja työhyvinvoinnin edistämiselle. Tämän tutkimuksen tavoitteena oli tutkia työyhteisön kehittämisen yhteyttä työhyvinvointiin ja kykyyn osallistavien työhyvinvoinnin kehitysprojektien tuloksena. Tutkimus täydentää aikaisempaa työhyvinvointitutkimusta ja selvittää yrityksissä toteu-tettujen kehitysprojektien vaikutuksia seuraavien kysymysten kautta: 1) Miten työhyvin-vointi kehittyi yrityksissä vähintään vuoden seuranta-aikana, 2) Mitkä tekijät ja toimen-piteet edistävät henkilöstön subjektiivisesti kokemaa työhyvinvointia tutkimuksen kohdeorganisaatioissa, 3) Mitkä tekijät vaikuttavat projektien onnistumiseen. Tutkimus tehtiin yhteistyössä Teknologiateollisuus ry:n kanssa ja hyödyntäen 'Hyvä työ Pidempi työura' hankkeen 'Yksilö tutka'- kyselyaineistoa. Tästä aineistosta valittiin lisensiaatintutkimuksen tausta-aineistoksi 18 yrityksen kyselyjen tilastoaineisto, joka perustui vuonna 2011 (n=2970) ja vuosina 2012 13 (n=2512) suoritettuihin kyselyihin. Tilastoaineiston perusteella tutkija valitsi 10 yritystä laadullisen tutkimuksensa kohteeksi: viisi työhyvinvoinnissa hyvin edistynyttä, kolme jonkin verran edistynyttä ja kaksi työhyvinvoinnin kannalta taantunutta yritystä. Tutkija suoritti haastattelut vuosina 2013 2014. Kvalitatiivinen aineisto koostuu 43 henkilön haastattelusta. Aiemmin tutkimuksessa vahvistettua 'Työkykytalo mallia' käytettiin tutkimuksen teoreettisena viitekehyksenä. Laadullisena menetelmänä käytettiin puolistrukturoituja haastatteluja. Yrityksissä käytettiin osallistavana kehittämismenetelmänä 'Työpaikka tutka'-menetelmää. Tutkimus luo uutta tietoa työhyvinvointia ja työkykyä edistävistä tekijöistä sekä työhyvinvoinnin johtamisen ja kehittämisen mallin. Tutkimuksen tulokset vahvistavat, että työyhteisön kehittämisellä on myönteinen vaikutus henkilöstön työhyvinvointiin ja työkykyyn. Johdon sitoutuminen kehittämistyöhön ja sen tavoitteisiin on tärkeä edellytys työyhteisön hyvinvoinnin edistämiselle ja menestyvälle kehitystyölle organisaatioissa.
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    Managing Corporate Social Responsibility in global supply networks
    (2014) Kortelainen, Ketty; Linnanen, Lassi; Tuotantotalouden laitos; Perustieteiden korkeakoulu; School of Science; Tanskanen, Kari
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    Hyperympyrän sovellus sekaelementtimenetelmään
    (2014) Malm, Torsten; Juntunen, Mika; Perustieteiden korkeakoulu; Perustieteiden korkeakoulu; School of Science; Stenberg, Rolf
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    Tuotannon suunnittelu ja johtaminen perusterveydenhuollossa: laajuusetu sähköisen asioinnin ja avovastaanottotoiminnan yhteistuotannossa
    (2012) Huttunen, Nora; Peltokorpi, Antti; Tuotantotalouden laitos; Perustieteiden korkeakoulu; School of Science; Lillrank, Paul
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    Modeling uncertainties in portfolio decision analysis
    (2012) Vilkkumaa, Eeva; Matematiikan ja systeemianalyysin laitos; Perustieteiden korkeakoulu; School of Science; Salo, Ahti
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    Machine learning methods for data security
    (2012) Hegedüs, József; Lendasse, Amaury; Perustieteiden korkeakoulu; Perustieteiden korkeakoulu; School of Science; Orponen, Pekka
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    Process facilitation in the context of global team work
    (2012) Haukola, Timo Juhani; Jaatinen, Miia; Tuotantotalouden laitos; Perustieteiden korkeakoulu; School of Science; Smeds, Riitta
    This study examines a distinct form of team facilitation, that of process facilitation, in the context of synchronously working global virtual teams, Differences in cultures, languages, and organizations between the members of global virtual teams give rise to "boundaries," which affect team processes and performance in many ways, This study explores the relationship between process facilitation and the ability of global virtual teams to overcome these boundaries. The study can be conceptualized as a qualitative case study that follows a research strategy known as Systematic combining, The theoretical framework used in the study is developed by synthesizing literature on virtual team work and process facilitation, Process facilitation is defined according to the work of Edgar Schein, I draw on practice theoretical research and define intra-team boundary crossing as team problem solving. The data used in the study consists of 126 hours of video-recorded virtual team meetings, The data was gathered from a university-level course organized by five universities situated on three different continents, Team working in this course was conducted in real time, Data analysis was conducted in four consequent phases: First, problematic situations were identified from the data, Second, the way these problematic situations were solved by the teams was analysed, Third, the effect of process facilitation on these situations was assessed. Fourth, the work of the process facilitators was analysed on a speech act level. The investigated student teams faced and solved shared problems related to team communication and coordination. In my analysis, I found that the problems related to communication were solved by the teams through knowledge deployment, while problems related to coordination often required new knowledge development Process facilitators gave support for team communication and maintained a propitious atmosphere for collaboration. However, there were differences in the behaviour of the facilitators: When the problematic situation was simple in nature, the facilitators expressed more task-oriented speech acts, whereas when the problem was complex in nature, facilitators expressed more socio-emotional speech acts. The study contributes to literature on virtual team work by clarifying what successful team facilitators do in practice. On the basis of the findings, a new theoretical framework regarding the effect of process facilitation on collaborative problem solving in the context of global virtual teams is presented. In addition, three propositions are presented: First, it is proposed that process facilitation affects positively intra-team communication and collaboration, Second, task-oriented speech acts by a virtual process facilitator are proposed to be more beneficial than socio-emotional speech-acts when a team is solving a problem that can be perceived to be mundane, Third, socio-emotional speech acts by a process facilitator are proposed to have a positive effect on problem solving when a team is working on a complex problem.
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    Impact of demand and supply uncertainties in decision models for operations management
    (2012) Käki, Anssi; Salo, Ahti; Matematiikan ja systeemianalyysin laitos; Perustieteiden korkeakoulu; School of Science; Salo, Ahti
    Companies which operate in uncertain environments can use stochastic decision models for purposes such as maximization of expected profit or minimization of risks. This Thesis studies how operational uncertainties impact the recommendations offered by decision models for supply chain management. The key uncertainties in these models pertain to the demand of products or components; the supplier's capability to deliver components; and the interdependencies between these uncertainties. Both continuous and discrete (scenario based) probability distributions are used, and particular attention is given to the qualitative characteristics of these distributions, such as asymmetry or bimodality. The results suggest that careful modelling of uncertainties can significantly improve the validity of decision models. This conclusion is reached by, for example, analysing how the shape of distribution impacts the expected profit of a company when the expected value and variance of the demand distribution are fixed. Moreover, it is shown how interdependencies between variables can be modelled with copula functions, and how the structure of interdependencies contributes to the recommendations of multivariate models. The value of distributional information is also considered. Although the results are exemplified with models from the manufacturing domain, they can be extended to other decision models as well.
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    Theory and applications of marker-based augmented reality
    (2012) Siltanen, Sanni; Tossavainen, Timo; Tietojenkäsittelytieteen laitos; Perustieteiden korkeakoulu; School of Science; Oja, Erkki
    Augmented Reality (AR) employs computer vision, image processing and computer graphics techniques to merge digital content into the real world. It enables real-time interaction between the user, real objects and virtual objects. AR can, for example, be used to embed 3D graphics into a video in such a way as if the virtual elements were part of the real environment. In this work, we give a thorough overview of the theory and applications of AR. One of the challenges of AR is to align virtual data with the environment. A marker-based approach solves the problem using visual markers, e.g. 2D barcodes, detectable with computer vision methods. We discuss how different marker types and marker identification and detection methods affect the performance of the AR application and how to select the most suitable approach for a given application. Alternative approaches to the alignment problem do not require furnishing the environment with markers: detecting natural features occurring in the environment and using additional sensors. We discuss these as well as hybrid tracking methods that combine the benefits of several approaches. Besides the correct alignment, perceptual issues greatly affect user experience of AR. We explain how appropriate visualization techniques enhance human perception in different situations and consider issues that create a seamless illusion of virtual and real objects coexisting and interacting. Furthermore, we show how diminished reality, where real objects are removed virtually, can improve the visual appearance of AR and the interaction with real-world objects. Finally, we discuss practical issues of AR application development, identify potential application areas for augmented reality and speculate about the future of AR. In our experience, augmented reality is a profound visualization method for on-site 3D visualizations when the user's perception needs to be enhanced.
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    Organising a maternity care service network
    (2011) Venesmaa, Julia; Linna, Miika Kämäräinen, Vesa; Tuotantotalouden laitos; Perustieteiden korkeakoulu; School of Science; Lillrank, Paul
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    Mikä palkitsee? - Aineeton palkitseminen valtionhallinnossa tapaustutkimusten valossa
    (2011) Handolin, Ville-Valtteri; Juuti, Pauli; Tuotantotalouden laitos; Perustieteiden korkeakoulu; School of Science; Saarinen, Esa
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    Product development expert problem representations
    (2011) Björklund, Tua; Vartiainen, Matti; Tuotantotalouden laitos; Perustieteiden korkeakoulu; School of Science; Vartiainen, Matti
    Studying product development expertise, i.e. the systematic successful solving of product development problems, can provide the foundation for product development training and education by informing what skills and knowledge are required. In contrast to much-studied well-defined problems, product development professionals address vague, wicked problems, like many knowledge workers. Defining and structuring these problems has a major influence on subsequent product development problem solving, and demands considerable levels of skill. However, previous research has been largely based on students, or at best, individual experts, and several open questions remain. This thesis explores the differences in the initial problem representations of real-life product development problems between advanced product development engineering students and recommended, professional experts. Seven experts and seven novices read five design briefs and completed a structured interview on each design brief. Their answers were segmented into individual propositions, and these segments were categorized based on thematic similarity in a bottom-up coding process. Differences between the novice and expert segments in each category were compared both qualitatively and statistically utilizing the Mann Whitney U test. The experts demonstrated representations that were superior in extent, depth and level of detail. They elicited more interconnections both within the problem information and between the problem and previous knowledge. The expert representations seemed also to be more geared towards action, with experts restricting their efforts towards solving the problems, taking a more proactive role in finding information, and having more detailed plans on how to proceed. The novices not only were more limited in activity, but spent more effort on evaluating the problem presentation and aimed to gain ready answers for their questions from the clients. The results indicate that targeting relevancy perceptions, problem structuring skills, and especially accommodating for interconnections in the representations can be a key factor in developing product development education to better match the requirements faced by professionals and enable successful product development problem solving.
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    Organizational resistance in strategic change projects: A case study in pharmaceutical industry
    (2011) Hildén, Leif; Martinsuo, Miia; Tuotantotalouden laitos; Perustieteiden korkeakoulu; School of Science; Artto, Karlos
    Development triggers change. Old solutions are in the past and new ones are ahead, which we create, try to adopt or adapt to. The opposite of change is inertia and resistance. Resistance to change originates from many different sources. The investigation at hand studied resistance to a strategic change that was in response to a change in the national and international patent legislation. The literature review explicates the difficulty of changes as demonstrated by the low success rates, 30% for change projects and only 10% for strategy Implementation. Second order changes like strategic changes are known to receive more resistance than first order or incremental changes. The research questions are: what kind of resistance is present, how does the resistance take place, who is resisting and what kind of variation in resistance is observed over time. Special attention is paid to understand the relationship on one hand between the elements of a change project and resistance and on the other hand between the project as a temporary organization and resistance. The objective is to find responses to how resistance can be anticipated and avoided in strategic change projects. Empirical evidence points at two groups of resistance, distorted perception and action disconnects. Company and corporate culture has a great impact on the resistive behaviour. The view of the project through the lenses of a temporary organization demonstrates the crucial importance of commitment and legitimacy building to avoid resistance. Furthermore, the study emphasizes the importance of leadership, the influence on stakeholders and the detrimental effect of communication barriers. Compared to other investigations, this one utilized a broad spectrum of resistance. Previous researches have used 24 types of resistance, but the literature review was able to identify 42 in addition. Without the expansion of types about one third of the resistance would have stayed uncovered in this study. The study confirms earlier findings, which show that with time, success of a firm causes inertia with rigid structure and culture. Traditionally resistance is thought to be practiced by change recipients, but this research shows that the project team, the leader and stakeholders can possess a lot of resistance. When generalizing the findings, an indication can be discerned showing the importance of project commitment and legitimacy in the implementation the strategy, in order to avoid resistance. From a managerial point of view, leadership and resistance seem to make a pair of antagonists. Strong and skilful leadership with an efficient conflict resolution mechanism can overtake the resistance and utilize it for reinforcing the change effort.
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    Review of the fuel performance code ENIGMA
    (2011) Tulkki, Ville; Salomaa, Rainer; Teknillisen fysiikan laitos; Perustieteiden korkeakoulu; School of Science; Salomaa, Rainer
    This thesis contains a review of the current state of VTT-modified ENIGMA v5.9b as it is at the end of the year 2010. The work is based on a report done as a part of SAFIR2010 (SAfety of FInnish Reactors 2010) programme POKEVA. The thesis contains a description of the fuel rod and the phenomena affecting it on a theoretical level ENIGMA interface is described and the ENIGMA simulation models are examined. The performance of the code is assessed versus several fuel experiments. As a summary, while ENIGMA is functional software for fuel performance modelling, many of its models are quite old. According to current knowledge some of them are based on incomplete understanding of the phenomena in question. While it is possible to adjust empirical models to match various experiment results, this approach is not valid. On the other hand, no conclusive evidence can be made based on single experiments. Therefore it is suggested that a comprehensive validation system should be developed prior to any major overhaul of ENIGMA.
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    A wave equation model for vowels: Measurements for validation
    (2011) Palo, Pertti; Malinen, Jarmo; Matematiikan ja systeemianalyysin laitos; Perustieteiden korkeakoulu; School of Science; Eirola, Timo
    This thesis presents a procedure for simultaneous recording of anatomic and acoustic data on speech production. The thesis also presents a mathematical model of vowel production and its pilot implementation as frequency domain numerical simulator. The model is based on the wave equation. The anatomic data is recorded with MRI and the acoustic data with a purpose built, MRI compatible sound recording setup. Both modalities of the data will be used in building the next generation of the simulator, estimating its parameters, and validating it. Compared with previous contributions in this area, the acoustic and anatomic data are more closely matched and, hence, the procedure more informative. The main scientific contribution is the description of the sound recording arrangement as well as the guidelines and considerations detailed for simultaneous data acquisition in MRI.