Silmäile
Hakuohje

Osuva

Osuva on Vaasan yliopiston avoin julkaisuarkisto. Osuva sisältää Vaasan yliopiston omat julkaisut, opinnäytteet ja tieteellisten artikkeleiden rinnakkaistallenteet. Osuvaan sisältyy julkaisujen viitetietoja, tiivistelmiä ja kokotekstejä. Sähköisten arkistokokoelmien sisältö ei ole luettavissa verkossa.

Kokoelmat Osuvassa

Viimeksi tallennetut

  • Mandatory cybersecurity disclosure: Early evidence from 10-K reports
    Haapamäki, Elina; Sihvonen, Jukka (Elsevier, 2026)
    Artikkeli
    This study provides early evidence on U.S. public companies’ responses to the SEC’s 2023 rule requiring detailed annual disclosures on cybersecurity risk management and governance. Using textual analysis of 3,440 Item 1C disclosures in 10-K filings from 2024, we investigate the determinants of these newly required disclosure characteristics and assess market reactions. Results show variation in disclosure quality—proxied by length, redundancy, and specificity—primarily driven by firm size, financial performance, auditor quality, cybersecurity and litigation risk exposures, and peer practices, though these factors collectively explain only moderate variance. Past cyber incidents, firm digitalization, material IT weaknesses, and tech-firm status show no influence, suggesting strategic discretion persists even under a mandate. Additional analyses show that Item 1C represents new disclosure content rather than a relocation of existing risk disclosures. To assess market reactions, we utilize event studies, analyze cybersecurity-related discussions in earnings call transcripts, and examine investor attention through filing download activity. The results indicate a minimal response from both investors and analysts to these newly mandated disclosures. These insights hold important implications for policymakers regarding the balance between regulatory burden and informational value, as jurisdictions globally adopt similar cybersecurity disclosure policies.
  • Attribution of Responsibility for Short-Duration Voltage Variations in Power Distribution Systems via QGIS, OpenDSS, and Python Language
    de Souza, Arthur Gomes; Passatuto, Luiz Arthur Tarralo; Bernardes, Wellington Maycon Santos; Freitas, Luiz Carlos Gomes; Resende, Enio Costa (IEEE, 2025)
    Artikkeli
    Short-Duration Voltage Variations (SDVVs) are phenomena that significantly impact power quality. Although they typically last no longer than three minutes, such events can disrupt load operations and cause substantial production losses. This study presents an enhanced methodology for determining whether an SDVV event originates upstream or downstream of the point of common coupling between two agents interconnected through a transformer. Building upon the work of Ferreira et al., whose original approach was applied to a circuit using MATLAB/Simulink, this research advances the methodology by applying it to both real and benchmark distribution systems using open-source tools, namely QGIS, OpenDSS, and Python™. The well-known IEEE 34-Bus Test System has been used to verify the methodology’s generalizability. The method was also further validated through tests conducted on two actual Brazilian distribution feeders in Uberlândia, Minas Gerais: one supplying large industrial consumers such as a rice mill and a carbonated beverages factory, and the other serving a municipal wastewater treatment plant and a large photovoltaic plant. By using real, detailed and georeferenced data, the approach ensures an accurate representation of both the network topology and the installed equipment. The results confirm that the proposed methodology reliably identifies the origin of SDVV events. A key contribution of this study is that the attribution of responsibility remains robust regardless of variations in transformer winding configurations, fault resistance, circuit topology, load characteristics, or the presence of distributed generation. These findings demonstrate the accessibility, robustness and practical applicability, offering a valuable tool for utilities and researchers aiming to enhance power quality and accountability in distribution networks.
  • A comparative study of the modified high voltage olivine-phosphate LiMPO4 (M = Fe, Mn, Co, Ni) as promising cathode materials for next-generation rechargeable batteries
    Manfo, Theodore Azemtsop; Laaksonen, Hannu (Elsevier, 2026)
    Artikkeli
    The growing demand for energy storage has driven extensive research into advanced cathode materials for lithium-ion batteries (LIBs), where cathode chemistry critically governs safety, cost, and electrochemical performance. Olivine lithium metal phosphates (LiMPO4) are promising cathode candidates due to their structural robustness and thermal stability. Rietveld refinement confirms an orthorhombic olivine structure (Pnma), with lithium occupying octahedral sites and Mn2+ and Co2+ substituting for Fe2+. Cell parameters and unit-cell volume increase with Mn substitution; while LiFePO4 (LFP) exhibits favorable electrochemical stability, LiMnPO4 (LMP) offers higher operating potential but suffers from sluggish lithium intercalation kinetics. Recent studies demonstrate that partial substitution with Co and Ni can significantly enhance electrochemical performance by modifying lithium diffusion pathways and energetics within the olivine framework. This paper summarizes recent progress on olivine cathodes, including LiCoPO4 (LCP) and LiNiPO4 (LNPO), which exhibit operating potentials exceeding 5.0 V versus Li+/Li. Strategies to overcome intrinsic limitations, such as particle size reduction, surface modification, and cation doping, are critically discussed, highlighting clear correlations between structure and electrochemical behavior. Key material descriptors, including cohesive energy, lithium intercalation energetics, and electrochemical stability, are examined. Finally, emerging opportunities and remaining challenges for olivine phosphates in solid-state and aqueous energy storage systems are outlined, providing a forward-looking perspective for next-generation LIB development.
  • Harnessing wind energy: Can it become a strategic driver of national energy security and the global energy transition?
    Balcerzak, Adam P.; Igliński, Bartłomiej; Pietrzak, Michał Bernard; Dutta, Anupam; Uddin, Gazi Salah (Institute of Economic Research, 2026)
    Artikkeli
  • Just-in-Time & Just-in-Case toimintamallien yhdistäminen kokoonpanotuotannossa : Toimintamallien tehokas optimointi kokoonpanotuotannossa
    Mäensivu, Jani (2026-04-08)
    Kandidaatintutkielma
    Tämän tutkielman aiheena on Just-in-Time (JIT) ja Just-in-Case (JIC) -toimintamallien yhdistäminen kokoonpanoteollisuudessa. Työn tarkoituksena on tutkia, miten näiden kahden mallin synergiaa voidaan hyödyntää toimitusketjun hallinnan tehokkuuden ja resilienssin parantamiseksi. Erityistä huomiota kiinnitetään kriittisten komponenttien hallintaan ja toimintamallien strategiseen yhteensovittamiseen, jotka ovat keskeisiä kokoonpanoteollisuuden globaalissa liiketoimintaympäristössä. Tutkielma toteutetaan kirjallisuuskatsauksena, ja tutkimusaineisto koostuu vertaisarvioiduista tieteellisistä artikkeleista, alan julkaisuista ja empiirisistä tapaustutkimuksista. Näitä lähteitä analysoimalla pyritään selvittämään JIT- ja JIC-mallien vahvuudet ja heikkoudet sekä parhaita käytäntöjä niiden yhdistämiseen kokoonpanoteollisuudessa.The subject of this thesis is the integration of Just-in-Time (JIT) and Just-in-Case (JIC) operational models in the assembly industry. The purpose of this study is to examine how the synergy between these two models can be leveraged to improve the efficiency and resilience of supply chain management. Particular attention is paid to the management of critical components and the strategic coordination of operational models, which are central to the global business environment of the assembly industry. The study is conducted as a literature review, and the research material consists of peer-reviewed scientific articles, industry publications, and empirical case studies. By analyzing these sources, the study aims to identify the strengths and weaknesses of the JIT and JIC models, as well as best practices for combining them in the assembly industry.