Modeling and Control of the Power Conversion Unit in a Solid Oxide Fuel Cell Environment

In this doctoral thesis, a power conversion unit for a 10 kWsolid oxide fuel cell is modeled, and a suitable control system is designed. The need for research was identified based on an observation that there was no information available about the characteristics of the solid oxide fuel cell from the perspective of power electronics and the control system, and suitable control methods had not previously been studied in the literature. In addition, because of the digital implementation of the control system, the inherent characteristics of the digital system had to be taken into account in the characteristics of the solid oxide fuel cell (SOFC). The characteristics of the solid oxide fuel cell as well the methods for the modeling and control of the DC/DC converter and the grid converter are studied by a literature survey. Based on the survey, the characteristics of the SOFC as an electrical power source are identified, and a solution to the interfacing of the SOFC in distributed generation is proposed. A mathematical model of the power conversion unit is provided, and the control design for the DC/DC converter and the grid converter is made based on the proposed interfacing solution. The limit cycling phenomenon is identified as a source of low-frequency current ripple, which is found to be insignificant when connected to a grid-tied converter. A method to mitigate a second harmonic originating from the grid interface is proposed, and practical considerations of the operation with the solid oxide fuel cell plant are presented. At the theoretical level, the thesis discusses and summarizes the methods to successfully derive a model for a DC/DC converter, a grid converter, and a power conversion unit. The results of this doctoral thesis can also be used in other applications, and the models and methods can be adopted to similar applications such as photovoltaic systems. When comparing the results with the objectives of the doctoral thesis, we may conclude that the objectives set for the work are met. In this doctoral thesis, theoretical and practical guidelines are presented for the successful control design to connect a SOFC-based distributed generation plant to the utility grid.

Knowledge, processes and relationships in organizational change: Understanding how to facilitate management of intellectual capital in diverse organization structures and cultures.

This study examined relationships of organizational dependencies, change management and developed intellectual knowledge resources, in different intellectual capital based development programs on ICT-sector. Study was carried out in a research context, where high degree of external organizational contingencies existed and lots of changes in several development programs had taken place in the last years. From a scientific perspective the main contribution was that evidence between relationships of organizational dependencies, change model portfolio and developed knowledge resources could be suggested. From managerial perspective the primary implication was that in situations where sustainable competitive advantage is pursued by means of increasing knowledge based productivity of labor, firms should seek to pursue organizational settings where external dependencies have minimal amount of effect.

Prosessiajattelun soveltaminen taloushallinnon tarpeisiin: case merkkitavaran vähittäismyyjä

Tämän Pro gradu -tutkielman tavoitteena on löytää prosessikirjallisuudesta kohdeyrityksen taloushallinnon kehittämiseen soveltuvia menetelmiä ja tunnistaa taloushallinnosta ne osa-alueet, joiden parantamisesta olisi yritykselle hyötyä tulevaisuudessa. Tutkielmassa sovelletaan kvalitatiivista analyysitapaa ja tutkimusstrategiana on tapaustutkimus. Aineistonkeruu suoritetaan empiirisen osion osalta haastattelujen, kyselyn ja havainnoinnin avulla. Teoreettinen viitekehys rakentuu taloushallinnon entistä strategisemman roolin ympärille etsien apukeinoja johtamiseen sekä prosessi- että laatuajattelusta. Tutkielmassa kartoitetaan kohdeyrityksen taloushallinnon prosessit sekä mallinnetaan niiden kulku ja rajapinnat muiden prosessien kanssa. Lisäksi tuodaan esiin prosesseissa piilevät kriittiset pisteet ja kehityskohteet. Kehitysehdotuksia esitetään myös kohdeyrityksen taloushallinnon organisoinnin ja laskentatoimen teorian vertailun sekä prosessiajattelun eri sovellusmahdollisuuksien pohjalta.

Development of agnostic mobile applications with cross-platform cloud computing platforms

Smart phones became part and parcel of our life, where mobility provides a freedom of not being bounded by time and space. In addition, number of smartphones produced each year is skyrocketing. However, this also created discrepancies or fragmentation among devices and OSes, which in turn made an exceeding hard for developers to deliver hundreds of similar featured applications with various versions for the market consumption. This thesis is an attempt to investigate whether cloud based mobile development platforms can mitigate and eventually eliminate fragmentation challenges. During this research, we have selected and analyzed the most popular cloud based development platforms and tested integrated cloud features. This research showed that cloud based mobile development platforms may able to reduce mobile fragmentation and enable to utilize single codebase to deliver a mobile application for different platforms.

Decision making and decision support in service systems

This thesis is a literature study that develops a conceptual model of decision making and decision support in service systems. The study is related to the Ä-Logi, Intelligent Service Logic for Welfare Sector Services research project, and the objective of the study is to develop the necessary theoretical framework to enable further research based on the research project results and material. The study first examines the concepts of service and service systems, focusing on understanding the characteristics of service systems and their implications for decision making and decision support to provide the basis for the development of the conceptual model. Based on the identified service system characteristics, an integrated model of service systems is proposed that views service systems through a number of interrelated perspectives that each offer different, but complementary, implications on the nature of decision making and the requirements for decision support in service systems. Based on the model, it is proposed that different types of decision making contexts can be identified in service systems that may be dominated by different types of decision making processes and where different types of decision support may be required, depending on the characteristics of the decision making context and its decision making processes. The proposed conceptual model of decision making and decision support in service systems examines the characteristics of decision making contexts and processes in service systems, and their typical requirements for decision support. First, a characterization of different types of decision making contexts in service systems is proposed based on the Cynefin framework and the identified service system characteristics. Second, the nature of decision making processes in service systems is proposed to be dual, with both rational and naturalistic decision making processes existing in service systems, and having an important and complementary role in decision making in service systems. Finally, a characterization of typical requirements for decision support in service systems is proposed that examines the decision support requirements associated with different types of decision making processes in characteristically different types of decision making contexts. It is proposed that decision support for the decision making processes that are based on rational decision making can be based on organizational decision support models, while decision support for the decision making processes that are based on naturalistic decision making should be based on supporting the decision makers’ situation awareness and facilitating the development of their tacit knowledge of the system and its tasks. Based on the proposed conceptual model a further research process is proposed. The study additionally provides a number of new perspectives on the characteristics of service systems, and the nature of decision making and requirements for decision support in service systems that can potentially provide a basis for further discussion and research, and support the practice alike.

Visual analytics for behavioral and niche market segmentation

Companies require information in order to gain an improved understanding of their customers. Data concerning customers, their interests and behavior are collected through different loyalty programs. The amount of data stored in company data bases has increased exponentially over the years and become difficult to handle. This research area is the subject of much current interest, not only in academia but also in practice, as is shown by several magazines and blogs that are covering topics on how to get to know your customers, Big Data, information visualization, and data warehousing. In this Ph.D. thesis, the Self-Organizing Map and two extensions of it – the Weighted Self-Organizing Map (WSOM) and the Self-Organizing Time Map (SOTM) – are used as data mining methods for extracting information from large amounts of customer data. The thesis focuses on how data mining methods can be used to model and analyze customer data in order to gain an overview of the customer base, as well as, for analyzing niche-markets. The thesis uses real world customer data to create models for customer profiling. Evaluation of the built models is performed by CRM experts from the retailing industry. The experts considered the information gained with help of the models to be valuable and useful for decision making and for making strategic planning for the future.

Hälsa i vårdande gemenskap : gemenskapens betydelse för äldre

The aim of the study and research questions: The aim of this study is to illuminate how caring communion can aid in promoting health as becoming in elderly people in the context of natural caring. The target group of the study consists of elderly citizens living at home. The focus of this thesis is on the concept of communion and how caring communion can affect the inner health resources in a patient’s inner health domain, as well as how caring communion can support health as becoming and inner health resources in the elderly. The main research questions of this study are the following: 1) what does communion mean? 2) what does caring communion mean? 3) what is the connection between caring communion and health? Theoretical perspective: The theoretical perspective of this qualitative study relies on the caritative caring theory as developed by scholars of caring sciences at the Åbo Academi University’s Vasa unit. The caritas motive is based on an ethos built on a consideration of togetherness, i.e. caring communion, a place where one feels at home and where one can be the person one was meant to be. Methodology: A hermeneutic research approach based on Gadamer (1997) permeates the study. This entails that understanding and interpretation become central. The study conducted in the thesis is divided into three sub-studies. Sub-study one and two are based on ontological determination whereas the third sub-study is carried out by contextual determination. The first sub-study is conducted by etymological and semantic analysis of the concept of communion (gemenskap) based on Koort (1975) and the second sub-study by determining the basic epistemological category of the concept based on Eriksson (2010b). Sub-study three is conducted through content analysis of 18 multidisciplinary and 13 caring science articles and dissertations based on Kvale (2009). The aim in the third sub-study is to define caring communions in various contexts of meaning based on Eriksson´s model of conceptual determination (2010b). All studies are interpreted through hermeneutic interpretation where the continuous movement from a part of a whole, to the whole, to part again, leads to new understanding. Finally, the findings from all the three sub-studies are compared to the concepts of pre-understanding and the inner-health-domain model of Wärnås (2002). Results: The results of the study offer a description of the dimensions of caring communion and a model that illuminates how caring communion can further health as becoming. The fundamentals of caring communion rest on the idea of a human being’s absolute right to dignity as a base for communion. The concept of communion contains a moral, an ethical, and a spiritual component. In communion, there exists a moral and ethical responsibility and a willingness to commit oneself. The individual is part of a connection or relation and knows the aim and course for the communion. A caring connection, a caring culture, a caring atmosphere and caring listening are characteristics of caring communion. In caring communion, the elderly feel trusting and see themselves as unique, powerful, and valuable. The model demonstrates that when the elderly are able to rest in caring communion, the virtues of courage and faith become strong and desire for life awaken within the elderly and health as becoming becomes possible. Conclusions: The outcome of the study is that all communion is not necessarily caring communion. In order for communion to be caring and for the elderly to achieve health as becoming, there are certain criteria that must be met. This is especially important when designing activities for the elderly in the context of natural caring.

Asiakasarvopohjaisten palveluiden kehittäminen kiinteistöpalvelualan yrityksessä

Tämän työn tavoitteena oli tutkia asiakasarvopohjaisten palveluiden kehittämistä ja luoda kiinteistöpalvelualan yritykselle kehitysprosessimalli, jonka avulla yritys voisi optimoida toimintojaan tulevaisuudessa. Tutkimuksen päätavoitteina oli tutkia asiakasarvoa kiinteistöpalveluissa, kartoittaa potentiaalisten uusien asiakkaiden palveluiden nykytila ja toiveet sekä tarkastella kohdeyrityksen palveluiden kehitysprosessia. Työn teoreettisessa osiossa tarkasteltiin palveluliiketoimintaa yleisellä tasolla, yrityksen palveluprosessin kehittämistä, asiakasarvon muodostumista sekä SERVQUAL- ja QFD-työkalujen avulla palvelun laatua ja asiakastarpeita. Työn teoriaosuuden kautta saatiin myös selville, että asiakasarvon hallinta on palveluiden kehitysprosessin ydin. Tutkimuksen empiirinen aineisto kerättiin syvähaastatteluiden avulla avainasiakkailta eri asiakassegmentteihin liittyen. Haastattelujen analysoinnissa hyödynnettiin laadullista sisällönanalyysiä. Työn tuloksissa määriteltiin asiakasarvo ja tärkeimmät asiakastarpeet kiinteistöpalveluissa, kartoitettiin asiakkaiden odotusten ja nykytilan väliset kuilut sekä luotiin yritykselle palveluiden kehitysprosessimalli, jota yritys voi toiminnoissaan tapauskohtaisesti hyödyntää tulevaisuudessa.

Tietokantaratkaisuehdotus pientasajännitesähköverkoston mittausdatavarastoksi

Lappeenrannan teknillinen yliopisto tutkii pientasajännitesähkön käyttöä. Yliopisto on rakennuttanut Järvi-Suomen Energia Oy:n ja Suur-Savon Sähkö Oy:n kanssa yhteistyössä kokeellisen pientasajännitesähköverkon, jolla pystytään tarjoamaan kenttäolosuhteet pienjännitetutkimukselle todellisilla asiakkailla ja todentaa LVDC-teknologiaa ja muita älykkään sähköverkon toimintoja kenttäolosuhteissa. Verkon tasajänniteyhteys on rakennettu 20 kV sähkönjakeluverkon ja neljän kuluttajan välille. 20 kV keskijännite suunnataan tasamuuntamolla ±750 V pientasajännitteeksi ja uudestaan 400/230 V vaihtojännitteeksi kuluttajien läheisyydessä. Tämän kandidaatintyön tarkoituksena on luoda yliopistolle tietokanta pientasajännitesähköverkosta kertyvälle tiedolle ja mittaustuloksille. Tietokanta nähtiin tarpeelliseksi luoda, jotta pienjänniteverkon mittaustuloksia pystytään myöhemmin tarkastelemaan yhdessä ja yhtenäisessä muodossa. Yhdeksi tutkimuskysymykseksi muodostui, kuinka järjestää ja visualisoida kaikki verkosta palvelimille kertyvä mittausdata. Työssä on huomioitu myös kolme tietokantaa mahdollisesti hyödyntävää käyttäjäryhmää: kotitalousasiakkaat, sähköverkkoyhtiöt ja tutkimuslaboratorio, sekä pohdittu tietokannan hyötyä ja merkitystä näille käyttäjille. Toiseksi tutkimuskysymykseksi muodostuikin, mikä kaikesta tietokantaan talletetusta datasta olisi oleellisen tärkeää ottaa talteen näiden asiakkaiden kannalta, ja kuinka nämä voisivat hakea tietoa tietokannasta. Työn tutkimusmenetelmät perustuvat jo valmiiksi olemassa olevaan mittausdataan. Työtä varten on käytetty sekä painettua että sähköisessä muodossa olevaa kirjallisuutta. Työn tuloksena on saatu luotua tietokanta MySQL Workbench -ohjelmistolla, sekä mittausdatan keräys- ja käsittelyohjelmat Python-ohjelmointikielellä. Lisäksi on luotu erillinen MATLAB-rajapinta tiedon visualisoimista varten, jolla havainnollistetaan kolmen asiakasryhmän mittausdataa. Tietokanta ja sen tiedon visualisointi antavat kuluttajalle mahdollisuuden ymmärtää paremmin omaa sähkönkäyttöään, sekä sähköverkkoyhtiöille ja tutkimuslaboratorioille muun muassa tietoa sähkön laadusta ja verkon kuormituksesta.