Browsing by Author "Lehtinen, Timo"

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Bottom-up Adoption of Continuous Delivery in a Stage-Gate Managed Software Organization
(2016) Laukkanen, Eero; Lehtinen, Timo; Itkonen, Juha; Paasivaara, Maria; Lassenius, Casper
A4 Artikkeli konferenssijulkaisussa
Context: Continuous delivery (CD) is a development practice for decreasing the time-to-market by keeping software releasable all the time. Adopting CD within a stage-gate managed development process might be useful, although scientific evidence of such adoption is not available. In a stage-gate process, new releases pass through stages and gates protect low-quality output from progressing. Large organizations with stage-gate processes are often hierarchical and the adoption can be either top-down, driven by the management, or bottom-up, driven by the development unit. Goal: We investigate the perceived problems of bottom-up CD adoption in a large global software development unit at Nokia Networks. Our goal is to understand how the stage-gate development process used by the unit affects the adoption. Method: The overall research approach is a qualitative single case study on one of the several geographical sites of the development unit. We organized two 2-hour workshops with altogether 15 participants to discover how the stage-gate process affected the adoption. Results: The stage-gate development process caused tight schedules for development and process overhead because of the gate requirements. Moreover, the process required using multiple version control branches for different stages in the process, which increased development complexity and caused additional branch overhead. Together, tight schedule , process overhead and branch overhead caused the lack of time to adopt CD. In addition, the use of multiple branches limited the available hardware resources and caused delayed integration. Conclusions: Adopting CD in a development organization that needs to conform to a stage-gate development process is challenging. Practitioners should either gain support from the management to relax the required process or reduce their expectations on what can be achieved while conforming to the process. To simplify the development process, the use of multiple version control branches could be replaced with feature toggles.
Development of solid oxide fuel cell and electrolyser system simulation tools
(2024-08-29) Karvetti, Kai
Kemian tekniikan korkeakoulu | Master's thesis
The shift away from fossil fuels is necessary to avoid greenhouse gas emissions that cause climate change and damage to the environment. An attractive opinion towards carbon-free society is hydrogen economy. However, in today’s world, majority of hydrogen is produced from fossil fuels. Essential element towards widespread green hydrogen economy are efficient electrolysis and fuel cell technologies to sustainably produce, use and refine hydrogen. Solid oxide is among the most promising and up-and-coming fuel cell and electrolysis technologies due to high efficiency and effective process integration. In this thesis, solid oxide electrolysis system simulations were built to study the performance, heat balance and mass balance of the systems. The goal of the thesis was to validate a process simulation software, DWSIM, based on experimental data with another simulation software, Aspen Plus, and to create steady state simulation models of various solid oxide electrolysis system concepts with DWSIM. The results showed that both simulation software present very similar results and the differences were minimal. Therefore, it can be concluded that DWSIM is an appropriate tool for steady state simulation of solid oxide electrolysis systems. The simulation of the electrolysis system concepts displayed system efficiencies of 81%-91%, which are corresponding to commercially available solid oxide electrolysis systems.
Juurisyyanalyysin soveltaminen ohjelmistoprojektien retrospektiiveissä
(2013-04-26) Viljanen, Juha
Perustieteiden korkeakoulu | Bachelor's thesis
Maa- ja metsätalousalueiden käsittelystä ja suunnittelusta maalaiskuntien pienalaisissa kaavoituksissa
(1968) Lehtinen, Timo
Helsinki University of Technology | Master's thesis
Measuring software maintainability
(2015-08-24) Viljanen, Juha
Perustieteiden korkeakoulu | Master's thesis
Maintenance forms the major part of the software's development costs. Keeping the software's code base in a good shape, i.e. maintainable, speeds up and reduces the cost of making changes and makes them less risky. Refactoring and reengineering are practices to improve a software's maintainability. An essential part of keeping a software's maintainability at a desired level or systematically improving its maintainability is to measure the progress and to find the parts of code whose improvement would have the biggest affect on the overall maintainability. This can be done by using metrics. It is crucial to make sure the metrics are actively used by the company personnel. This can be done by providing useful deployment practices for the metrics. A literature review and a case study was conducted using a simplified version of the Design Science. The aim was to find a relevant set of metrics and useful ways of deploying them at the case company. In the case study, workshops were organized at the case company to fulfill the aim. Out of the suggested metrics the three top prioritized ones were implemented in a automated metrics system. The analyzed files were prioritized based on the file activity. An aggregated index was calculated out of the three metrics to provide a quick overview on the situation. Out of the suggested deployment ideas two deployment practices were prototyped. A reactive way is proposed for monitoring the change in the maintainability of the code base and a proactive way for systematically reducing the technical debt by identifying the most problematic places in the code base whose refactoring would most benefit the total maintainability of the software. The implemented metrics system and the prototyped deployment practices were presented and evaluated at the case company and were found useful. Apart from the three company specific code measures, the results should be generally applicable to any Scrum organization that aims to control and systematically repay its quality debt. The organization can use a similar approach as described in this thesis to find out their unique set of top priority technical debt issues to measure. The process was applied in a multi-site Scrum organization and hence applied techniques that fit well distributed teams. The deployment practices utilize cloud services making them useful to distributed teams.
Miksi ketterän ohjelmistotiimin tuotokset eivät vastaa tuoteomistajien odotuksia. Tapaustutkimus isossa kansainvälisessä ohjelmistotuoteyrityksessä.
(2014-08-21) Virtanen, Risto
Perustieteiden korkeakoulu | Master's thesis
Monet ohjelmistoprojektit eivät valmistu tavoitetussa ajassa tai niiden budjetti ylittyy. Yksi haaste ohjelmistoprojekteissa on vaatimusten kommunikointi yrityksen sisällä tuoteomistajalta tuotteen kehittäjille niin, että haluttu viesti menee perille. Kommunikointi voi kuitenkin olla vaikeaa, koska tuoteomistajat edustavat liiketaloudellista puolta, kun taas kehittäjät teknillisempää puolta. Jos kommunikointi jää puutteelliseksi, voi lopputulos olla erilainen, kuin tuoteomistaja olisi ajatellut. Tässä työssä pyritään ratkaisemaan ohjelmistotuoteyrityksen ongelmaa, miksi toteutukset eivät vastaa tuoteomistajien odotuksia. Ongelman syitä kerätään ohjelmistotiimien retrospektiiveissa. Tunnistetut syyt luokitellaan ryhmiin ja tarkastellaan, millaisia suhteita syiden rymillä on toisiinsa. Lisäksi tarkastellaan, mitä samoja ryhmiä eri retrospektiiveissä tunnistetaan. Tunnistettujen syiden ja ryhmittelyiden avulla kehitettiin neljä ratkaisuideaa, joista osa otettiin käyttöön. Ratkaisuideoita arvioitiin haastattelemalla ohjelmistotiimien jäseniä. Suurin osa tunnistetuista ongelmista sijoittui vaatimusten hallintaan. Vaatimuksia ei kuvattu tarpeeksi selkeästi ja tarkasti, eikä niitä kommunikoitu tarvittavan hyvin kehittäjille. Tämä aiheutti sen, että kehittäjät eivät tarkalleen tienneet toiminnallisuuksien tarkoitusta, jolloin toteutus ei vastannut odotusta. Kolme käyttöönotettua ratkaisuideaa keskittyivät vaatimusten hallintaan ja vaatimusten kommunikoimiseen kehittäjille. Ratkaisuideat saivat hyvää palautetta ja ne ovat auttaneet tuotteen laadun parantamisessa. Ratkaisuideoista saadun palautteen perusteella voidaan sanoa, että tutkimus oli kannattava kohdeyritykselle, koska haluttuja ongelmia saatiin korjattua. Seuraavaksi voitaisiin tehdä samankaltainen tutkimus uudestaan ja selvittää minkälaisia ongelmia nyt tunnistettaisiin ja tunnistettaisiinko ratkaistuja syitä enää.
A model for the optimization of operations for customer related cost calculation in the process industry
(1993) Lehtinen, Timo
Helsinki University of Technology | Master's thesis
Sodium Borohydride Hydrogen Generator System for a Free-breathing PEM Fuel Cell
(2006) Lehtinen, Timo
Helsinki University of Technology | Master's thesis
Polymeeripolttokenno (PEMFC) on energiakonversiolaite, joka käyttää vedyn ja hapen kemiallista energiaa tuottaessaan sähköä ja lämpöä. Vapaastihengittävä PEMFC saa hapen suoraan ympäröivästä ilmasta kun taas vety kuljetetaan erillisessä säiliössä. Tavallisimmat vedyn varastointitavat ovat massiivisia ja kalliita, joten tässä työssä keskitytään vaihtoehtoiseen varastointimenetelmään. Natriumborohydridi on turvallinen kemikaali, jolla on korkea vetypitoisuus. Kemikaaliin sitoutunut vety voidaan vapauttaa hydrolyysissa katalyytin avulla. PEMFC:n suorituskyky on samanlainen sekä generaattorilla tuotetulla vedyllä että 5.0 laboratoriolaadun vedyllä. Työssä suunniteltiin ja rakennettiin vetygeneraattorijärjestelmä ja tarvittava ohjauselektroniikka vapaastihengittävälle polttokennolle. Laitteistolla saavutettiin 50 minuutin käyttöaika.
Use of a quality monitoring methodology and platform in industrial software development – A feasibility study
(2016-02-15) Lindqvist, Pia
Sähkötekniikan korkeakoulu | Master's thesis
Ensuring software quality is important for achieving a competitive advantage in the market. Also, it is essential in critical systems, where a computer program cannot fail under any circumstances. In software projects, the best way to accomplish quality is to continuously monitor the state of the product and the development process. This means, that measurements on the software have to be done. However, as it is not adequate to measure everything, the relevant quality characteristics have to be defined. This is very context-specific and should thus be done for each project separately. In this thesis, the deployment of quality monitoring in software development projects was studied. This included defining a quality model and designing, deploying and using a quality monitoring program. These activities were facilitated by the U-QASAR methodology and platform that provide guidance and support for quality monitoring by measurement data integration. The study consisted of two parts: a multiple case study and constructive research. The case study was conducted to explore the case project members’ experiences on quality monitoring. Observations, interviews and questionnaires were used as research instruments. A constructive research method was used to evaluate the data integration in the U-QASAR platform. Data integration adapters were explored and developers were interviewed and finally a new adapter was implemented. In both parts, thematic analysis was used to process the data. The case study results showed that quality monitoring can be deployed even in small-scale software projects, but there are certain challenges. For example, it is difficult to connect objective software measurements to more abstract quality objectives. Moreover, practitioners’ knowledge on the terminology of software measurement and software quality is not something that can be assumed. However, it is important that the semantic structure is taken care of in order to achieve common understanding. The constructive research revealed needs for further development regarding the data integration architecture of the U-QASAR platform.
Valtamerihinaajan hinauslaitteiston valinta
(1987) Lehtinen, Timo
Helsinki University of Technology | Master's thesis