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Developer social networks / open source project networks : how programmers use GitHub
Get PDFOpen-source software (OSS) development has become increasingly collaborative and distributed. Platforms such as GitHub play a pivotal role in shaping both technical contributions and social interactions. This research examines GitHub as a developer social network (DSN), investigating how contributors interact with projects, assume roles, and utilize platform features. Emphasis is placed on understanding the factors that motivate participation and influence the long-term sustainability of open-source software (OSS) communities.
A mixed-methods approach was adopted, incorporating a review of relevant literature, survey responses from active contributors, and an analysis of interaction patterns. The findings indicate that contributors operate in fluid roles, influenced by a combination of intrinsic motivations and social recognition mechanisms. GitHub’s features, such as pull requests, issues, and discussion threads, facilitate collaboration and foster a sense of community, although challenges like maintainer fatigue and uneven participation remain prevalent.
Sustainability is found to be multidimensional, encompassing technical resilience, community health, and contributor well-being. By aligning empirical observations with established theoretical frameworks, this study contributes to a deeper understanding of the sociotechnical structures that underpin the development of open-source software (OSS). The results offer practical implications for platform designers, project maintainers, and researchers interested in supporting sustainable open-source ecosystems
Impact of hybrid work on sense of belonging and resilience among software professionals
Get PDFThe emergence of hybrid work models after the COVID-19 pandemic has changed the way of operations among software teams, reducing face-to-face interactions and challenging traditional workplace dynamics. In such settings, it is important to understand the experiences of the team members, especially the emotional and social factors influencing the employee welfare and team dynamics. This study examines the impact of hybrid work on the sense of belonging and resilience among software professionals.
A qualitative approach was adopted, using semi-structured interviews with 10 participants from five multinational IT companies. Thematic analysis was conducted using both inductive and deductive coding, guided by Self-Determination Theory with the concepts of autonomy, relatedness, and competence.
Findings reveal that physical presence alone does not guarantee belonging. Instead, the quality of interpersonal interactions, emotional connection, and inclusive practices, such as regular check-ins, camera-on meetings, and proactive leadership, play a critical role. Employees who felt supported and connected demonstrated stronger resilience, while those lacking engagement or informal interaction showed signs of isolation and reduced motivation. The study recommends promoting a camera-on culture during virtual meetings to enhance connection and reduce distractions. Meeting facilitators should actively engage remote participants through questions and prompts. Additionally, team-level informal activities, such as virtual fun hours, are encouraged to strengthen belonging among the team members working in hybrid settings
The role of the consumer behavior in the creation of a sustainable supply chain in the beauty industry
Get PDFConsumers are concerned about the environmental issues, social problems, and working conditions throughout the beauty industry, which has prompted consumers to demand sustainable beauty products that align with their beliefs.
This research aims to identify the role of consumer behavior in the creation of a sustainable supply chain in the beauty industry. This study shows the different sustainable tendencies implemented by beauty companies and NGOs through partnerships with suppliers to achieve and improve agricultural practices and working conditions. Furthermore, it identifies the limitations and challenges that companies have encountered while implementing a sustainable supply chain.
Following the analysis of the academic and grey literature. It is established that consumers are considered an external pressure for companies to create and implement a sustainable supply chain. Their demands and insight have an impact on the financial performance, product development, and supplier selection. Additionally, there were presented examples of implementing sustainable supply chains in different industries, therefore showing the possibility for the beauty industry to follow other industries.
Improving efficiency by applying Lean principles
No full textTämä opinnäytetyö on saatavissa LUT-yliopiston arkistosta. Ota yhteyttä: [email protected]äivän merkittävän kilpailukykyiset markkinat vaativat yrityksiltä joustavaa tuotantoa ja laadukkaita tuotteita. Asiakastarpeisiin vastaaminen kustannustehokkaasti edellyttää yrityksiä tunnistamaan arvoa tuottavat ja arvoa tuottamattomat toimet tilaus-toimitusketjussaan. Vähentämällä merkittävästi arvoa tuottamattomia toimia yritys pystyy keskittymään tehokkaaseen toimintaan.
Tässä diplomityössä tarkastellaan kohdeyrityksen tuotannon nykytilaa. Lähtötilanteen selvittämiseksi työssä suoritettiin nykytila analyysi. Analyysin avuksi valmistettiin arvovirtakartta sekä havainnointi ja määrällinen tutkimus. Analyysin pohjalta havainnollistettiin yrityksen arvoa tuottamattomia toimia. Työssä on tarkasteltu myös syitä erilaisiin arvoa tuottamattomiin toimiin sekä niiden vaikutusta tehokkuuteen.
Työn tavoitteena oli selvittää, voidaanko arvoa tuottamattomia toimia vähentää merkittävästi tuotannossa. Nykytila-analyysin pohjalta luotiin kehityskohteet arvoa tuottamattomien toimien vähentämiseksi tuotannossa.In today’s highly competitive market environment, companies are required to have flexible production and deliver high-quality products. Meeting customer needs in a cost-efficient manner requires companies to identify both value-adding and non-value-adding activities within their supply-chain. By significantly reducing non-value-adding activities, the company can focus on efficient operations.
This thesis examines the current state of production at the case company. To establish the baseline, a current state analysis was conducted. As part of the analysis, a value stream map was created and both observational and quantitative research methods were used. Based on the analysis, the company’s non-value-adding activities were visualized. The thesis also explores the root causes of various non-value-adding activities and their impact on operational efficiency.
The objective of the study was to determine whether non-value-adding activities in production could be significantly reduced. Based on the current state analysis, development targets were created to reduce non-value-adding activities in the production process
Customer segmentation of corporate customers in financial industry
No full textOikein toteutetun asiakassegmentoinnin avulla yritys voi tunnistaa arvokkaimmat asiakkaansa ja parantaa toimintansa tehokkuutta. Asiakassegmentointi tarkoittaa asiakkaiden jaottelemista osajoukkoihin valittujen muuttujien samankaltaisuuden perusteella.
Tässä diplomityössä tutkittiin asiakkaiden segmentointia asiakkaan arvon muodostavien muuttujien avulla. Työ toteutettiin tapaustutkimuksena, missä hyödynnettiin ryhmäkeskusteluita yrityksen tavoitteiden ja odotusten ymmärtämiseksi. Tutkimuksen kirjallisuuskatsauksessa käsitellään asiakkaiden segmentointia, luodaan asiakkaiden segmentoinnin yleinen prosessi sekä havainnollistetaan aiemmassa tutkimuksessa eniten käytettyjä asiakkaan segmentoinnin menetelmiä.
Diplomityön ratkaisuvaiheessa tutkittiin kohdeyrityksen asiakassegmentoinnin nykyistä mallia ja luotiin ehdotus uudesta mallista. Asiakkaista muodostettiin aineisto asiakkaan arvon muodostavien komponenttien perusteella, minkä jälkeen asiakkaat pisteytettiin. Tämän jälkeen asiakkaita segmentoitiin hyödyntämällä K-Means klusterointialgoritmia. Algoritmi jaottelee asiakkaat euklidisen etäisyyden avulla samankaltaisten asiakkaiden kanssa samoihin segmentteihin.
Asiakkaiden arvon komponenttien ja klusterointialgoritmin yhdistelmällä asiakkaat saatiin jaoteltua samankaltaisiin ryhmiin, joista oli helposti tunnistettavissa arvokkaimmat segmentit. Malli onnistui erottamaan eri tuoteryhmien parhaat asiakkaat sekä useamman tuoteryhmän asiakkaat toisistaan. Työssä vertailtiin segmentoinnin tuloksia asiakkaiden edellisvuoden tuottoihin. Vertailun tuloksena huomattiin, että algoritmi onnistui jaottelemaan asiakkaat myös toteutuneiden tuottojen osalta oikeisiin segmentteihin. Useamman tuotekategorian yritysten tulee keskittyä eri tuotekategorioiden vertailukelpoisuuteen, mutta muuten perinteinen klusterointialgoritmi soveltui asiakkaiden segmentointiin hyvin.Properly implemented customer segmentation allows a company to identify its most valuable customers and improve the efficiency of its operations. Customer segmentation means dividing customers into subsets based on the similarity of selected variables.
The master’s thesis focuses on the financial industry’s customer segmentation based on customer value components. Thesis is carried out as a case study, which exploits group discussions to comprehend case companies’ challenges and needs for customer segmentation. In the literature review of the thesis, customer segmentation is discussed, and based on previous literature, common customer segmentation process is constructed. Literature review also discusses previous research about customer segmentation in the financial industry.
The thesis evaluated the case company’s current customer segmentation model and proposed a new one. The data set used in the solution was conducted based on results of group discussions and includes components of customer value, after which the customers were scored. The dataset is then applied to the K-Means clustering algorithm, which divides customers into groups by using Euclidean distance.
Results indicate that the research approach was successful, and each segment had different characteristics. Most profitable customers from each product segment were also identified. The work compared the segmentation results with the customers' revenues from the previous year. The comparison showed that the algorithm was able to divide the customers into the correct segments based on their actual revenues. Companies with multiple product categories should focus on the comparability of different product categories, but otherwise the traditional clustering algorithm was well suited for customer segmentation
Ilmastodatan tarkkuuden parantaminen diffuusiomallien avulla
No full textDiffusion models are a type of deep learning method applicable for generating high-quality image data. They have also been proven suitable for super-resolution tasks, where low-resolution inputs are transformed to high-resolution outputs. Diffusion models are trained to generate samples from Gaussian noise by learning to reverse a noising, or diffusion, process. Flow matching is another technique related to diffusion, where the data is linearly transformed from the input distribution to achieve the target sample. Climate downscaling refers to a model aiming to improve the resolution of coarse climate data. These models can be used to gain more detailed information from coarse climate inputs, such as predictions of future climate scenarios. In this thesis, a climate downscaling method was implemented using both diffusion models and flow matching. For temperature data, both methods proved efficient, with flow matching achieving the lowest error. For more complex atmospheric water data, the initial experiments were also comparable to baseline solutions. Additionally, suitable physical constraints were found for both models, resulting in moderate improvements in the error. These generative models show potential for being applied to larger-scale climate downscaling.Diffuusiomallit ovat syväoppimismenetelmä, jonka avulla voidaan esimerkiksi luoda korkea-laatuisia kuvia. Niitä voidaan käyttää myös superresoluutioon, jossa matalan tarkkuuden syötteestä muunnetaan korkeatarkkuuksinen. Diffuusiomallit koulutetaan generoimaan näytteitä normaalijakautuneesta kohinasta käänteisen kohinan syötyön, eli diffuusioprosessin, avulla. Virtausten sovitus (engl. Flow Matching) on diffuusiomallien kaltainen tekniikka, jossa data pyritään muuntamaan lähtöjakaumasta lineaarisen muunnoksen avulla haluttuun jakaumaan. Karkean ilmastodatan tarkkuutta voidaan parantaa erilaisten mallien avulla. Näiden mallien avulla saadaan tarkempaa informaatiota karkeasta ilmastodatasta, kuten tulevaisuutta mallintavista skenaarioista. Tässä diplomityössä kehitettiin ilmastodatan tarkennusmalli sekä diffuusiomallin, että virtausten sovituksen avulla. Mallit olivat suorituskykyisiä lämpötiladatalle, ja virtausten sovitukse tekniikalla saatiin alhaisin havaintovirhe. Myös ilmakehän veden määrää käytettiin muuttujana, joka osoittautui lämpötilaa vaikeaselkoisemmaksi. Tällakin datalla saadut alustavat tulokset ovat vertailukelpoisia perusmallien kanssa. Lisäksi, kummalekin mallille saatiin sovitettua fysikaalisia rajoitteita, joiden avulla mallin tuottamaa tulosta voitiin edelleen parantaa. Nämä generatiivisiet mallit osoittavat potentiaalia myös suuremman kokoluokan ilmastodatan tarkennukseen
Profitability of energy storage systems in the residential sector : an analysis of energy storage systems in Finland
Get PDFThis thesis focuses on the economic viability of residential energy storage systems (ESS) with integrated photovoltaic (PV) systems in Finland. The thesis evaluates how market conditions, policy structures and technical specifications influence the economic performance of small-scale battery storage solutions for private homeowners. The study uses hourly data of household electricity consumption, solar energy production and spot prices to create an Excel model of a PV-battery system located in the city of Helsinki. Despite self-sufficiency and self-consumption rates of 52.4% and 45.6% respectively, the payback period of the system’s investment spanned over 60 years due to the lack of subsidies and compensation for exported energy. The study explains that policy incentives, the structure of tariffs and seasonal variations are key in deciding whether it is economically viable to invest in a home energy storage system. The findings of this thesis indicate that ESSs are not a financially attractive option for homeowners in the current state of the energy market. However, policy reforms to further incentivise the use of these systems could make them much more attractive and increase the speed in which they are deployed in homes in Finland
Social impacts of different energy storage options
Get PDFAs we are transitioning more and more towards renewable energy to address climate change, reduce greenhouse emission and ensure long term energy security. This thesis presents a systematic literature review (SLR) to comprehensively assess the social impacts associated with different energy storage options, including Lithium-ion Batteries (LIB), Pumped Hydro Energy Storage (PHES), Hydrogen Energy Storage (HES), Flow Batteries (FB). This study employs a structural SLR methodology to search for peer-reviewed journals, articles, and authoritative reports, with particular attention to Social Life Cycle Assessment (S-LCA) and Social Impact Assessment (SIA) frameworks. Key findings indicate considerable social hazards linked to Lithium-ion Batteries (LIBs), encompassing worker exploitation, community harm, and health and safety issues. Pumped Hydro Energy Storage (PHES) and flow batteries exhibit relatively diminished social risks, providing benefits in employment and community approval. The review identifies significant methodological inconsistencies, data gaps, and an underrepresentation of community-level and vulnerable stakeholder perspectives in current assessments. This work contributes to the development of more equitable and sustainable energy transitions by informing policy and practice with a holistic understanding of the social implications of energy storage technologies, aligned with global sustainability goals and the United Nations Sustainable Development Goals
Short circuit modeling of a daisy chain connected common DC system for determination of the worst-case short circuit scenario
No full textTässä diplomityössä tutkitaan yhteisellä välipiirillä varustetussa taajuusmuuttajajärjestelmässä tapahtuvan tasajännitevälipiirin napojen välisen oikosulun aiheuttamia vikavirtoja piirin eri osissa. Työssä muodostetaan simulaatio, jonka avulla selvitetään useista erilaisista piirikokoonpanoista pahin skenaario, jonka katsotaan olevan se, jossa mitataan piirin valituissa osissa suurimmat virran i²t-arvot. Skenaarioiden muuttujia ovat syöttöverkon jännite, syöttävän taajuusmuuttajan verkonpuoleinen kuristin, kaksi eri kokoista DC-sulaketta sekä vaihtoehto, jossa piiri on kokonaan ilman DC-sulaketta, kolme erilaista kuormalaitekokoonpanoa, sekä vian sijainti. Kaikista muuttujista muodostuu yhteensä 132 eri skenaariota, jotka simuloidaan pahimman skenaarion selvittämiseksi.
Simulaatiomallin muodostusta varten työssä suoritetaan myös impedanssimittauksia eri komponenteille. Näiden avulla määritetään simulaatiossa käytettyjen komponenttien sähköisiä parametreja. Mallilla suoritetaan lisäksi vertailusimulaatiot, joiden tuloksia verrataan IEC 61660 -standardissa esitetyn oikosulkulaskennan metodin avulla saatuihin tuloksiin.
Tulosten perusteella tunnistetaan pahimmat skenaariot, mutta erot pahimpien skenaarioiden välillä ovat pieniä, jolloin yhtä selvästi muita pahempaa skenaariota ei ilmene. Tuloksista saadaan kuitenkin selville, että suurempi syöttöverkon jännite, sekä käytössä ollut syöttöverkonpuoleinen kuristin nostavat muuttujista merkittävimmin piirissä mitattuja virran i²t-arvoja. DC-sulakkeen eri vaihtoehtojen merkitys mitattuihin virran i²t-arvoihin on pieni, paitsi skenaarioissa, jossa vika tapahtuu syöttöyksikössä, jolloin käytössä ollut DC-sulake suojaa tehokkaasti vian ulkopuolelle jääviä kuormalaitteita. Vian sijainnin ei työssä havaita vaikuttavan merkittävästi piirissä mitattuihin virran i²t-arvoihin edellä mainittuja kuormalaitteita suojanneita skenaarioita lukuun ottamatta.This thesis studies short circuit currents occurring in a frequency converter system with a common DC-link when a fault happens between the poles of the DC-link. A simulation model is formed to analyze various circuit configurations and to determine the worst-case scenario. It is considered that the worst-case scenario is the one where the highest current i²t values are measured in the circuit. The circuit variables include the supply voltage, the AC-choke of the supply unit, two different sizes of DC-fuses as well as no DC-fuse option, three different load device configurations and different fault locations. In total 132 different scenarios are formed based on the variables and simulated to determine the worst-case scenario.
To build the simulation model, impedance measurements are carried out for various components. These measurements help define the electrical parameters of the components used in the simulation. In addition, comparative simulations are conducted, and the results are compared with those obtained using the short-circuit calculation method presented in IEC 61660 -standard.
According to results, the worst-cases are identified but the differences between highest-value-scenarios are minimal, meaning that no single scenario is significantly worse than the others. The results however reveal that a higher supply voltage and an AC-choke in the circuit before supply unit are the most significant factors affecting the measured i²t values in the circuit. The impact of different DC-fuse options on the measured i²t values is small, except in cases where the fault occurs in the supply unit where the DC-fuse protects the load devices. The fault location does not appear to significantly affect the measured i²t values except for the scenarios where the DC fuse protected the load devices
Waste heat assessment in performance testing at a high-speed turbocompressor manufacturing company
No full textEuroopan unioni on asettanut tavoitteet energiamurrokseen vastaamiseksi, ja jäsenvaltioita velvoitetaan tuomaan säädökset täytäntöön. Suomessa energiatehokkuuslaki edellyttää suuria yrityksiä teettämään energiakatselmuksen neljän vuoden välein. Tämä tutkimus vastaa suurnopeusturbokompressoreita valmistavan yrityksen viimeisimpään energiakatselmukseen, jossa tunnistettiin merkittävä hukkalämpöpotentiaali turbokompressorien suorituskykytestin aikaisessa poistoilman lämpenemisessä.
Tutkimuksen tavoitteena oli selvittää koeajoaseman hukkalämpöpotentiaali sekä arvioida lämmöntalteenoton mahdollisuudet ja kustannussäästöt. Menetelminä käytettiin kirjallisuuskatsausta lämmöntalteenottomenetelmien ja valintajärjestelmien tunnistamiseksi. Kohdeyrityksen hukkalämpöpotentiaalia arvioitiin mittausdataan perustuvilla energia- ja eksergia-analyyseillä. Lisäksi tarkasteltiin yleisesti turbokoneiden toimintaa ja turbokompressorien standardinmukaisen suorituskykytestin vaatimuksia.
Tulosten mukaan kohdeyrityksen koeajoasema tuottaa vuosittain noin 325 MWh korkealaatuista hukkalämpöä, josta suurin osa voidaan hyödyntää tuotantotilojen ja käyttöveden lämmityksessä. Optimaaliseksi ratkaisuksi löydettiin järjestely, joka kattaa jopa 41 prosenttia lämpökohteiden vuotuisesta energiatarpeesta ja hyödyntää 94 prosenttia hukkalämpöpotentiaalista riippuen lämmöntalteenoton hyötysuhteesta. Investoinnin takaisinmaksuaika on viisi vuotta, kun enimmäiskustannus on 90 585 euroa.
Tutkimus korostaa systemaattisen kartoituksen ja eksergia-analyysin merkitystä energiatehokkuusprojekteissa. Jatkokehityksenä kohdeyritys voi hyödyntää tuloksia lämmöntalteenoton teknisen toteutuksen suunnittelussa sekä sisällyttää hukkalämmön kartoituksen osaksi energiatehokkuushankkeiden arviointia.The European Union has set targets to respond to the energy transition, and all member states are required to implement corresponding regulations. The Finnish Energy Efficiency Act mandates that large companies are required to conduct energy audits every four years. This study responds to the latest energy audit of a company manufacturing high-speed turbocompressors, where a significant waste heat potential was identified in the exhaust air of the turbocompressors during performance testing.
The objective of the study was to assess the waste heat potential of the testing facility and to evaluate the possibilities for heat recovery and cost savings. The research methods included a literature review to identify heat recovery methods and selection criteria. The target company’s waste heat potential was assessed through energy and exergy analyses based on measurement data. In addition, the working principles of turbomachinery and the requirements of standardized turbocompressor performance testing were reviewed.
According to the results, the test facility of the target company generates approximately 325 MWh of high-quality waste heat annually. It was found that most of this energy can be utilized for heating of production facilities and domestic hot water. The optimal solution can meet up to 41 percent of the annual heating demand of heat sinks while recovering 94 percent of the available waste heat, depending on the efficiency of the heat recovery system. The payback period for the investment is five years, with a maximum cost of 90,585 euros.
The study highlights the importance of a systematic approach and the importance of exergy analysis in energy efficiency projects. As a next step, the target company can use the findings to design the technical implementation of the heat recovery and incorporate the waste heat analysis into the evaluation of energy efficiency initiatives